Clinical Focus

  • Abdominal Aortic Aneurysm
  • Endovascular Procedures
  • Carotid Artery Stenting
  • Thoracoabdominal Aortic Aneurysm
  • Mesenteric Vascular Occlusion
  • Thoracic Aortic Aneurysm
  • Intermittent Claudication
  • Angioplasty, Percutaneous Transluminal
  • Peripheral Arterial Disease
  • Carotid Stenosis
  • Complex aortic surgery
  • Endovascular aneurysm repair
  • Renal artery stenosis
  • Vascular Surgery

Academic Appointments

Administrative Appointments

  • Vice-Chair for Clinical Affairs, Department of Surgery, Stanford Medical School (2015 - Present)
  • Medical Director, Vascular Surgery Clinics, Stanford Health Care (2010 - Present)
  • Medical Director, Stanford Vascular Laboratory, Stanford Health Care (2010 - Present)
  • Medical Director, Ambulatory Specialty Care, Stanford Health Care (2010 - Present)
  • Service Medical Director, Stanford Health Care (2011 - Present)

Professional Education

  • Fellowship:University of Wisconsin (2006) WI
  • Residency:Stanford Hospital and Clinics - Dept of Surgery (1992) CA
  • Medical Education:Harvard Medical School (1987) MA
  • Board Certification: Vascular Surgery, American Board of Surgery (2007)
  • Board Certification: General Surgery, American Board of Surgery (1994)
  • M.D., Harvard University, Medicine (1987)
  • Residency, Stanford University, General Surgery (1992)
  • Fellowship, Stanford University, Transplant Surgery (1993)
  • Fellowship, University of Wisconsin, Vascular Surgery (2006)
  • Board Certification, Vascular Surgery, American Board of Surgery (2007)
  • Board Certification, General Surgery, American Board of Surgery (1994)

Research & Scholarship

Current Research and Scholarly Interests

Dr. Mell's research interest focus on comparative effectiveness of health care delivery for complex surgical diseases, including optimizing outcomes and cost effectiveness.

Dr. Mell's clinical interests include all aspects of vascular surgery, with a special emphasis on surgery for complex aortic disease, including endovascular repair of abdominal aortic aneurysm.

Clinical Trials

  • PRESERVE-Zenith® Iliac Branch System Clinical Study Recruiting

    The PRESERVE-Zenith® Iliac Branch System Clinical Study is a clinical trial to study the safety and effectiveness of the Zenith® Branch Endovascular Graft-Iliac Bifurcation in combination with the Zenith® Connection Endovascular Stent/ConnectSX™ covered stent in the treatment of aorto-iliac and iliac aneurysms.

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  • CHOICE: Carotid Stenting For High Surgical-Risk Patients Not Recruiting

    The purposes of this study is to 1) Provide additional information that the commercially available Abbott Vascular Carotid Stent Systems and Embolic Protection Systems can be used successfully by a wide range of physicians under commercial use conditions. 2) Provide an ongoing post-market surveillance mechanism for documentation of clinical outcomes and for possible extension of the Centers for Medicare and Medicaid Services (CMS) coverage to a broader group of patients.

    Stanford is currently not accepting patients for this trial. For more information, please contact Ronald Dalman, (650) 725 - 5227.

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  • Endurant Stent Graft System Post Approval Study Not Recruiting

    The purpose of the study is to demonstrate the long term safety and effectiveness of the Endurant Stent Graft System for the endovascular treatment of infrarenal abdominal aortic aneurysms in a post-approval environment, through the endpoints established in this protocol. The clinical objective of the study is to evaluate the long term safety and effectiveness of the Endurant Stent Graft System assessed at 5 years through freedom from Aneurysm-Related Mortality (ARM).

    Stanford is currently not accepting patients for this trial. For more information, please contact Ronald Dalman, (650) 725 - 5227.

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  • Endurant Bifurcated and Aorto-Uni-Iliac (AUI) Stent Graft System Not Recruiting

    To demonstrate safety and effectiveness of the Endurant Stent Graft in the treatment of Abdominal Aortic or Aorto-Uni-Iliac Aneurysms.

    Stanford is currently not accepting patients for this trial. For more information, please contact Jason Lee, (650) 725 - 5227.

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  • Zenith(R) Low Profile AAA Endovascular Graft Clinical Study Recruiting

    The Zenith® Low Profile AAA Endovascular Graft Clinical Study is a clinical trial approved by US FDA to study the safety and effectiveness of the Zenith® Low Profile AAA Endovascular Graft to treat abdominal aortic, aorto-iliac, and iliac aneurysms.

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  • Vorapaxar Study for Maturation of AV Fistulae for Hemodialysis Access Recruiting

    The Objectives of this study are: 1. To determine if vorapaxar safely improves arteriovenous (AV) fistula functional maturation when administered during the maturation process compared with placebo. 2. To determine if vorapaxar safely improves AV fistula patency, allowing for secondary procedures to aid in fistula maturation compared with placebo. 3. To determine if vorapaxar safely facilitates successful cannulation of AV fistulas for hemodialysis compared with placebo. This is a randomized placebo-controlled double-blind pilot trial. Study procedures will be conducted at Stanford University Medical Center, and standard-of-care (SOC) procedures will be conducted at Stanford and it's affiliated hospitals (Veteran's Affairs Palo Alto Health Care System and the Stanford Vascular Surgery Clinic at Valley Medical Center). The investigators expect to enroll 128 patients. Patients will be assigned to treatment groups with a 1:1 randomization in blocks of 4 at the conclusion of the AV fistula creation. Patients will be stratified based on fistula location (lower arm versus upper arm).

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2017-18 Courses


All Publications

  • Predictive models for mortality after ruptured aortic aneurysm repair do not predict futility and are not useful for clinical decision making JOURNAL OF VASCULAR SURGERY Thompson, P. C., Dalman, R. L., Harris, E. J., Chandra, V., Lee, J. T., Mell, M. W. 2016; 64 (6): 1617-1622


    The clinical decision-making utility of scoring algorithms for predicting mortality after ruptured abdominal aortic aneurysms (rAAAs) remains unknown. We sought to determine the clinical utility of the algorithms compared with our clinical decision making and outcomes for management of rAAA during a 10-year period.Patients admitted with a diagnosis rAAA at a large university hospital were identified from 2005 to 2014. The Glasgow Aneurysm Score, Hardman Index, Vancouver Score, Edinburgh Ruptured Aneurysm Score, University of Washington Ruptured Aneurysm Score, Vascular Study Group of New England rAAA Risk Score, and the Artificial Neural Network Score were analyzed for accuracy in predicting mortality. Among patients quantified into the highest-risk group (predicted mortality >80%-85%), we compared the predicted with the actual outcome to determine how well these scores predicted futility.The cohort comprised 64 patients. Of those, 24 (38%) underwent open repair, 36 (56%) underwent endovascular repair, and 4 (6%) received only comfort care. Overall mortality was 30% (open repair, 26%; endovascular repair, 24%; no repair, 100%). As assessed by the scoring systems, 5% to 35% of patients were categorized as high-mortality risk. Intersystem agreement was poor, with κ values ranging from 0.06 to 0.79. Actual mortality was lower than the predicted mortality (50%-70% vs 78%-100%) for all scoring systems, with each scoring system overestimating mortality by 10% to 50%. Mortality rates for patients not designated into the high-risk cohort were dramatically lower, ranging from 7% to 29%. Futility, defined as 100% mortality, was predicted in five of 63 patients with the Hardman Index and in two of 63 of the University of Washington score. Of these, surgery was not offered to one of five and one of two patients, respectively. If one of these two models were used to withhold operative intervention, the mortality of these patients would have been 100%. The actual mortality for these patients was 60% and 50%, respectively.Clinical algorithms for predicting mortality after rAAA were not useful for predicting futility. Most patients with rAAA were not classified in the highest-risk group by the clinical decision models. Among patients identified as highest risk, predicted mortality was overestimated compared with actual mortality. The data from this study support the limited value to surgeons of the currently published algorithms.

    View details for DOI 10.1016/j.jvs.2016.07.121

    View details for Web of Science ID 000390044000011

    View details for PubMedID 27871490

  • Unplanned reoperations after vascular surgery JOURNAL OF VASCULAR SURGERY Kazaure, H. S., Chandra, V., Mell, M. W. 2016; 63 (3): 731-737
  • Postoperative Surveillance and Long-term Outcomes After Endovascular Aneurysm Repair Among Medicare Beneficiaries JAMA SURGERY Garg, T., Baker, L. C., Mell, M. W. 2015; 150 (10): 957-963


    The Society for Vascular Surgery recommends annual surveillance with computed tomography (CT) or ultrasonography after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysms. However, such lifelong surveillance may be unnecessary for most patients, thereby contributing to overuse of imaging services.To investigate whether nonadherence to Society for Vascular Surgery-recommended surveillance guidelines worsens long-term outcomes after EVAR among Medicare beneficiaries.We collected data from Medicare claims from January 1, 2002, through December 31, 2011. A total of 9503 patients covered by fee-for-service Medicare who underwent EVAR from January 1, 2002, through December 31, 2005, were categorized as receiving complete or incomplete surveillance. We performed logistic regressions controlling for patient demographic and hospital characteristics. Patients were then matched by propensity score with adjusting for all demographic variables, including age, sex, race, Medicaid eligibility, residential status, hospital volume, ruptured abdominal aortic aneurysms, and all preexisting comorbidities. We then calculated differences in long-term outcomes after EVAR between adjusted groups. Data analysis was performed from January 1, 2002, through December 31, 2011.Post-EVAR imaging modality, aneurysm-related mortality, late rupture, and complications.Median follow-up duration was 6.1 years. Incomplete surveillance was observed in 5526 of 9695 patients (57.0%) who survived the initial hospital stay at a mean (SD) of 5.2 (2.9) years after EVAR. After propensity matching, our cohort consisted of 7888 patients, among whom 3944 (50.0%) had incomplete surveillance. For those in the matched cohort, patients with incomplete surveillance had a lower incidence of late ruptures (26 of 3944 [0.7%] vs 57 of 3944 [1.4%]; P = .001) and major or minor reinterventions (46 of 3944 [1.2%] vs 246 of 3944 [6.2%]; P < .001) in unadjusted analysis. Aneurysm-related mortality was not statistically different between groups (13 of 3944 [0.3%] vs 24 of 3944 [0.6%]; P = .07). In adjusted analysis of postoperative outcomes controlling for all patient and hospital factors by the tenth postoperative year, patients in the incomplete surveillance group experienced lower rates of total complications (2.1% vs 14.0%; P < .001), late rupture (1.1% vs 5.3%; P < .001), major or minor reinterventions (1.4% vs 10.0%; P < .001), aneurysm-related mortality (0.4% vs 1.3%; P < .001), and all-cause mortality (30.9% vs 68.8%, P < .001).Nonadherence to the Society for Vascular Surgery guidelines for post-EVAR imaging was not associated with poor outcomes, suggesting that, in many patients, less frequent surveillance is not associated with worse outcomes. Improved criteria for defining optimal surveillance will achieve higher value in aneurysm care.

    View details for DOI 10.1001/jamasurg.2015.1320

    View details for Web of Science ID 000367585200008

  • Adherence to postoperative surveillance guidelines after endovascular aortic aneurysm repair among Medicare beneficiaries JOURNAL OF VASCULAR SURGERY Garg, T., Baker, L. C., Mell, M. W. 2015; 61 (1): 23-27


    After endovascular aortic aneurysm repair (EVAR), the Society for Vascular Surgery recommends a computed tomography (CT) scan ≤30 days, followed by annual imaging. We sought to describe long-term adherence to surveillance guidelines among United States Medicare beneficiaries and determine patient and hospital factors associated with incomplete surveillance.We analyzed fee-for-service Medicare claims for patients receiving EVAR from 2002 to 2005 and collected all relevant postoperative imaging through 2011. Additional data included patient comorbidities and demographics, yearly hospital volume of abdominal aortic aneurysm repair, and Medicaid eligibility. Allowing a grace period of 3 months, complete surveillance was defined as at least one CT or ultrasound assessment every 15 months after EVAR. Incomplete surveillance was categorized as gaps for intervals >15 months between consecutive images as or lost to follow-up if >15 months elapsed after the last imaging.Our cohort comprised 9695 patients. Median follow-up duration was 6.1 years. A CT scan ≤30 days of EVAR was performed in 3085 (31.8%) patients and ≤60 days in 60.8%. The median time to the postoperative CT was 38 days (interquartile range, 25-98 days). Complete surveillance was observed in 4169 patients (43.0%). For this group, the mean follow-up time was shorter than for those with incomplete surveillance (3.4 ± 2.74 vs 6.5 ± 2.1 years; P < .001). Among those with incomplete surveillance, follow-up became incomplete at 3.3 ± 1.9 years, with 57.6% lost to follow-up, 64.1% with gaps in follow-up (mean gap length, 760 ± 325 days), and 37.6% with both. A multivariable analysis showed incomplete surveillance was independently associated with Medicaid eligibility (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.29-1.55; P < .001), low-volume hospitals (HR, 1.12; 95% CI, 1.05-1.20; P < .001), and ruptured abdominal aortic aneurysm (HR, 1.51; 95% CI, 1.24-1.84; P < .001).Postoperative imaging after EVAR is highly variable, and less than half of patients meet current surveillance guidelines. Additional studies are necessary to determine if variability in postoperative surveillance affects long-term outcomes.

    View details for DOI 10.1016/j.jvs.2014.07.003

    View details for Web of Science ID 000346637600004

    View details for PubMedID 25088738

  • Transposition of the Left Renal Vein for the Treatment of Nutcracker Syndrome in Children: A Short-term Experience ANNALS OF VASCULAR SURGERY Ullery, B. W., Itoga, N. K., Mell, M. W. 2014; 28 (8)
  • Interfacility transfer and mortality for patients with ruptured abdominal aortic aneurysm. Journal of vascular surgery Mell, M. W., Wang, N. E., Morrison, D. E., Hernandez-Boussard, T. 2014; 60 (3): 553-557


    Patients receiving interfacility transfer to a higher level of medical care for ruptured abdominal aortic aneurysms (rAAAs) are an important minority that are not well characterized and are typically omitted from outcomes and quality indicator studies. Our objective was to compare patients transferred for treatment of rAAAs with those treated without transfer, with particular emphasis on mortality and resource utilization.We linked longitudinal data from 2005 to 2010 Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases and Emergency Department Databases from California, Florida, and New York. Patients were identified using International Classification of Diseases-Ninth Revision-Clinical Modification codes. Our main outcome variables were mortality, length of stay, and cost. Data included discharge information on the transfer-out and transfer-in hospital. We used univariate and multivariate analysis to identify variables independently associated with transfer and in-hospital mortality.Of 4439 rAAA patients identified with intent to treat, 847 (19.1%) were transferred before receiving operative repair. Of those transferred, 141 (17%) died without undergoing AAA repair. By multivariate analysis, increasing age in years (odds ratio [OR] 0.98; 95% confidence interval [CI], 0.97-0.99; P < .001), private insurance vs Medicare (OR, 0.62; 95% CI, 0.47-0.80; P < .001), and increasing comorbidities as measured by the Elixhauser Comorbidity Index (OR, 0.90; 95% CI, 0.86-0.95; P < .001) were negatively associated with transfer. Weekend presentation (OR, 1.23; 95% CI, 1.02-1.47; P = .03) was positively associated with transfer. Transfer was associated with a lower operative mortality (adjusted OR, 0.81; 95% CI, 0.68-0.97; P < .02) but an increased overall mortality when including transferred patients who died without surgery (OR, 1.30; 95% CI, 1.05-1.60; P = .01). Among the transferred patients, there was no significant difference in travel distance between those who survived and those who died (median, 28.7 vs 25.8 miles; P = .07). Length of stay (median, 10 vs 9 days; P = .008), and hospital costs ($161,000 vs $146,000; P = .02) were higher for those transferred.The survival advantage for patients transferred who received treatment was eclipsed by increased mortality of the transfer process. Including 17% of transferred patients who died without receiving definitive repair, mortality was increased for patients transferred for rAAA repair compared with those not transferred after adjusting for demographic, clinical, and hospital factors. Transferred patients used significantly more hospital resources. Improving systems and guidelines for interfacility transfer may further improve the outcomes for these patients and decrease associated hospital resource utilization.

    View details for DOI 10.1016/j.jvs.2014.02.061

    View details for PubMedID 24768368

  • Payer Status, Preoperative Surveillance, and Rupture of Abdominal Aortic Aneurysms in the US Medicare Population. Annals of vascular surgery Mell, M. W., Baker, L. C. 2014; 28 (6): 1378-1383


    To determine the factors contributing to increased rate of ruptured abdominal aortic aneurysms (AAAs) for elderly poor patients.Medicare claims were analyzed for patients who underwent AAA repair from 2006 to 2009 with preoperative abdominal imaging. Repair for ruptured versus intact AAAs was our primary outcome measure. We used logistic regression to determine the relationship between Medicaid eligibility and the risk of rupture, sequentially adding variables related to patient characteristics, socioeconomic status, receipt of preoperative AAA surveillance, and hospital AAA volume. We then estimated the proportional effect of each factor.No differences in rupture were observed in women based on payer status. Medicaid-eligible men were more likely to present with ruptured AAA (odds ratio [OR] 2.42, 95% confidence interval [CI] 1.65-3.52). After adjusting for patient and hospital factors, the poor remained at higher risk for rupture (OR 1.5, 95% CI 1.10-2.26). This disparate risk of rupture was more commonly observed in hospitals treating a higher proportion of Medicaid-eligible patients. We estimate that 36% of the observed disparity in rupture for the elderly poor is explained by patient factors, 27% by gaps in surveillance, 9% by hospital factors, and <1% by socioeconomic factors.Incomplete preoperative surveillance is a key contributor to increased rupture of AAA in the elderly poor. Efforts aimed at improving disparities must include consistent access to medical care.

    View details for DOI 10.1016/j.avsg.2014.02.008

    View details for PubMedID 24530712

  • Gaps in preoperative surveillance and rupture of abdominal aortic aneurysms among Medicare beneficiaries. Journal of vascular surgery Mell, M. W., Baker, L. C., Dalman, R. L., Hlatky, M. A. 2014; 59 (3): 583-588


    Screening and surveillance are recommended in the management of small abdominal aortic aneurysms (AAAs). Gaps in surveillance after early diagnosis may lead to unrecognized AAA growth, rupture, and death. This study investigates the frequency and predictors of rupture of previously diagnosed AAAs.Data were extracted from Medicare claims for patients who underwent AAA repair between 2006 and 2009. Relevant preoperative abdominal imaging exams were tabulated up to 5 years prior to AAA repair. Repair for ruptured AAAs was compared with repair for intact AAAs for those with an early diagnosis of an AAA, defined as having received imaging at least 6 months prior to surgery. Gaps in surveillance were defined as no image within 1 year of surgery or no imaging for more than a 2-year time span after the initial image. Logistic regression was used to examine independent predictors of rupture despite early diagnosis.A total of 9298 patients had repair after early diagnosis, with rupture occurring in 441 (4.7%). Those with ruptured AAAs were older (80.2 ± 6.9 vs 77.6 ± 6.2 years; P < .001), received fewer images prior to repair (5.7 ± 4.1 vs 6.5 ± 3.5; P = .001), were less likely to be treated in a high-volume hospital (45.4% vs 59.5%; P < .001), and were more likely to have had gaps in surveillance (47.4% vs 11.8%; P < .001) compared with those receiving repair for intact AAAs. After adjusting for medical comorbidities, gaps in surveillance remained the largest predictor of rupture in a multivariate analysis (odds ratio, 5.82; 95% confidence interval, 4.64-7.31; P < .001).Despite previous diagnosis of AAA, many patients experience rupture prior to repair. Improved mechanisms for surveillance are needed to prevent rupture and ensure timely repair for patients with AAAs.

    View details for DOI 10.1016/j.jvs.2013.09.032

    View details for PubMedID 24246537

  • Modern advances in vascular trauma. Surgical clinics of North America Callcut, R. A., Mell, M. W. 2013; 93 (4): 941-961


    Early diagnosis and intervention are paramount for improving the likelihood of a favorable outcome for traumatic vascular injuries. As technology has rapidly diversified, the diagnostic and therapeutic approaches available for vascular injuries have evolved. Mortality and morbidity from vascular injury have declined over the last decade. The use of vascular shunts and tourniquets has become standard of care in military medicine.

    View details for DOI 10.1016/j.suc.2013.04.010

    View details for PubMedID 23885939

  • Impact of the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act on Abdominal Ultrasonography Use Among Medicare Beneficiaries ARCHIVES OF INTERNAL MEDICINE Shreibati, J. B., Baker, L. C., Hlatky, M. A., Mell, M. W. 2012; 172 (19): 1456-1462


    Since January 1, 2007, Medicare has covered abdominal aortic aneurysm (AAA) screening for new male enrollees with a history of smoking under the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act. We examined the association between this program and abdominal ultrasonography for AAA screening, elective AAA repair, hospitalization for AAA rupture, and all-cause mortality.We used a 20% sample of traditional Medicare enrollees from 2004 to 2008 to identify 65-year-old men eligible for screening and 3 control groups not eligible for screening (70-year-old men, 76-year-old men, and 65-year-old women). We used logistic regression to examine the change in outcomes at 365 days for eligible vs ineligible beneficiaries before and after SAAAVE Act implementation, adjusting for comorbidities, state-level smoking prevalence, geographic variation, and time trends.Fewer than 3% of abdominal ultrasonography claims after 2007 were for SAAAVE-specific AAA screening. There was a significantly greater increase in abdominal ultrasonography use among SAAAVE-eligible beneficiaries (2.0 percentage points among 65-year-old men, from 7.6% in 2004 to 9.6% in 2008; 0.7 points [8.9% to 9.6%] among 70-year-old men; 0.7 points [10.8% to 11.5%] among 76-year-old men; and 0.9 points [7.5% to 8.4%] among 65-year-old women) (P < .001 for all comparisons with 65-year-old men). The SAAAVE Act was associated with increased use of abdominal ultrasonography in 65-year-old men compared with 70-year-old men (adjusted odds ratio [AOR], 1.15; 95% CI, 1.11-1.19) (P < .001), and this increased use remained even when SAAAVE-specific AAA screening was excluded (AOR, 1.12; 95% CI, 1.08-1.16) (P < .001). Implementation of the SAAAVE Act was not associated with changes in rates of AAA repair, AAA rupture, or all-cause mortality.The impact of the SAAAVE Act on AAA screening was modest and was based on abdominal ultrasonography use that it did not directly reimburse. The SAAAVE Act had no discernable effect on AAA rupture or all-cause morality.

    View details for DOI 10.1001/archinternmed.2012.4268

    View details for Web of Science ID 000310070200005

    View details for PubMedID 22987204

  • Lower extremity computed tomography angiography can help predict technical success of endovascular revascularization in the superficial femoral and popliteal artery. Journal of vascular surgery Itoga, N. K., Kim, T., Sailer, A. M., Fleischmann, D., Mell, M. W. 2017


    Preprocedural computed tomography angiography (CTA) assists in evaluating vascular morphology and disease distribution and in treatment planning for patients with lower extremity peripheral artery disease (PAD). The aim of the study was to determine the predictive value of radiographic findings on CTA and technical success of endovascular revascularization of occlusions in the superficial femoral artery-popliteal (SFA-pop) region.Medical records and available imaging studies were reviewed for patients undergoing endovascular intervention for PAD between January 2013 and December 2015 at a single academic institution. Radiologists reviewed preoperative CTA scans of patients with occlusions in the SFA-pop region. Radiographic criteria previously used to evaluate chronic occlusions in the coronary arteries were used. Technical success, defined as restoration of inline flow through the SFA-pop region with <30% stenosis at the end of the procedure, and intraoperative details were evaluated.From 2013 to 2015, there were 407 patients who underwent 540 endovascular procedures for PAD. Preprocedural CTA scans were performed in 217 patients (53.3%), and 84 occlusions in the SFA-pop region were diagnosed. Ten occlusions were excluded as no endovascular attempt to cross the lesion was made because of extensive disease or concomitant iliac intervention. Of the remaining 74 occlusions in the SFA-pop region, 59 were successfully treated (80%) and 15 were unsuccessfully crossed (20%). The indications for revascularization were claudication in 57% of patients and critical limb ischemia in the remaining patients. TransAtlantic Inter-Society Consensus A, B, and C occlusions were treated with 87% success, whereas D occlusions were treated with 68% success (P = .047). There were nine occlusions with 100% vessel calcification that was associated with technical failure (P = .014). Longer lengths of occlusion were also associated with technical failure (P = .042). Multiple occlusions (P = .55), negative remodeling (P = .69), vessel runoff (P = .56), and percentage of vessel calcification (P = .059) were not associated with failure. On multivariable analysis, 100% calcification remained the only significant predictor of technical failure (odds ratio, 9.0; 95% confidence interval, 1.8-45.8; P = .008).Analysis of preoperative CTA shows 100% calcification as the best predictor of technical failure of endovascular revascularization of occlusions in the SFA-pop region. Further studies are needed to determine the cost-effectiveness of obtaining preoperative CTA for lower extremity PAD.

    View details for DOI 10.1016/j.jvs.2017.02.031

    View details for PubMedID 28502550

  • Under-Utilization of Routine Ultrasound Surveillance after Endovascular Aortic Aneurysm Repair. Annals of vascular surgery Mell, M. W., Garg, T., Baker, L. C. 2017


    Since 2009, the Society for Vascular Surgery has advocated annual surveillance imaging with ultrasound (US) after the first postoperative year for uncomplicated endovascular aneurysm repairs (EVARs). We sought to describe diffusion of US into long-term routine surveillance and to estimate potential cost savings among Medicare beneficiaries after EVAR.Using Medicare claims data, we identified patients receiving EVAR from 2002 to 2010 and included only those who did not subsequently have reinterventions, late aneurysm-related complications, or death. We collected all relevant postoperative imaging (computed tomography [CT] and US) through 2011. Patients with follow-up less than 1 year were excluded. We estimated cost savings with increased use of US after the first postoperative year.The cohort comprised 24,615 patients with a mean follow-up of 3.9 ± 2.3 years. Mean number of images decreased from 2.23 in the first postoperative year to 0.31 in the 10th year. Utilization of US at the first postoperative year remained low but increased from 15.2% in 2003 to 28.8% in 2011 (P < 0.001). By the 10th postoperative year, the proportion of patients receiving US increased from 8.2% to 37.8%, while use of CT only remained high but decreased from 60.8% to 42.1%. Mean cost of surveillance imaging was $2,132/CT and $234/US. Performing US in 50-75% of patients beginning 1 year after EVAR would decrease costs by 14-48%/year. This translates to a mean cost savings of $338-$1135 per imaged patient per year, with an estimated savings to Medicare of $155 million to $305 million over 10 years.CT remains the primary modality of surveillance for up to 10 years after EVAR for patients without reinterventions or aneurysm-related complications. Increasing the use of US and decreasing the use of CT would save cost without compromising outcomes.

    View details for DOI 10.1016/j.avsg.2017.03.203

    View details for PubMedID 28501663

  • Western Vascular Society guidelines for transfer of patients with ruptured abdominal aortic aneurysm JOURNAL OF VASCULAR SURGERY Mell, M. W., Starnes, B. W., Kraiss, L. W., Schneider, P. A., Pevec, W. C. 2017; 65 (3): 603-608


    When a patient with ruptured abdominal aortic aneurysm (rAAA) presents at a facility ill-equipped to provide care, transfer may provide the best chance for survival. Large distances and long travel times provide challenging barriers to prompt and appropriate care in the western United States.The Western Vascular Society (WVS) adopted a set of guidelines in considering transfer of a patient with an rAAA using published literature, membership survey and input, and existing recommendations. This article reports the guidelines and describes the process and rationale behind their development.Fifteen guidelines for transfer and care of rAAAs were endorsed by the WVS.When local care cannot be provided, transfer guidelines may standardize care for rAAAs and may be applicable across may practice settings.

    View details for DOI 10.1016/j.jvs.2016.10.097

    View details for Web of Science ID 000397987900027

    View details for PubMedID 28236914

  • An Untapped Resource: Left Renal Vein Interposition Graft for Portal Vein Reconstruction During Pancreaticoduodenectomy DIGESTIVE DISEASES AND SCIENCES Tran, T. B., Mell, M. W., Poultsides, G. A. 2017; 62 (1): 68-71

    View details for DOI 10.1007/s10620-016-4050-4

    View details for Web of Science ID 000392312200012

    View details for PubMedID 26825845

  • Anterior Retroperitoneal Spine Exposure following Prior Endovascular Aortic Aneurysm Repair. Annals of vascular surgery Ullery, B. W., Thompson, P., Mell, M. W. 2016; 35: 207 e5-9


    We describe successful anterior retroperitoneal spine exposure to facilitate anterior lumbar interbody fusion (ALIF) in a patient with a prior endovascular aneurysm repair (EVAR).A 74-year-old male with an extensive spine surgical history presented with progressive neurogenic claudication and paresthesia involving both feet. In addition, his surgical history was notable for an EVAR performed elsewhere 5 years earlier, with subsequent right renal stent placement for encroachment of the right renal artery. Diagnostic evaluation identified severe L3-4 and L4-5 canal stenosis, and a 48 × 36-mm aneurysm sac with a type II endoleak. Revision L3-L5 fusion from an anterior approach with vascular surgery assistance was recommended.The retroperitoneum was accessed through a left paramedian abdominal incision. The abdominal aortic aneurysm sac was visualized and noted to be nonpulsatile. The distal aorta and left iliac vessels were dissected and retracted medially to facilitate anterior exposure of the L3-4 and L4-5 disk spaces. Successful ALIF of the L3-5 vertebrae was then performed. Retractors were removed and the aortoiliac vessels were carefully returned to anatomic position. The aneurysm sac remained nonpulsatile, with normal pulses in the iliac arteries. Postoperative imaging demonstrated stable appearance of aortic stent graft. At 1-year follow-up, the patient reports complete resolution of symptoms and imaging demonstrates a patent aortic stent graft with a stable type II endoleak.Widespread application of ALIF will inevitably include an increasing subgroup of patients with previous EVAR. Such patients require thorough clinical and radiographic perioperative considerations for the access surgeon.

    View details for DOI 10.1016/j.avsg.2016.01.048

    View details for PubMedID 27238999

  • Metformin treatment status and abdominal aortic aneurysm disease progression JOURNAL OF VASCULAR SURGERY Fujimura, N., Xiong, J., Kettler, E. B., Xuan, H., Glover, K. J., Mell, M. W., Xu, B., Dalman, R. L. 2016; 64 (1): 46-?


    In population-based studies performed on multiple continents during the past two decades, diabetes mellitus has been negatively associated with the prevalence and progression of abdominal aortic aneurysm (AAA) disease. We investigated the possibility that metformin, the primary oral hypoglycemic agent in use worldwide, may influence the progression of AAA disease.Preoperative AAA patients with diabetes were identified from an institutional database. After tabulation of individual cardiovascular and demographic risk factors and prescription drug regimens, odds ratios for categorical influences on annual AAA enlargement were calculated through nominal logistical regression. Experimental AAA modeling experiments were subsequently performed in normoglycemic mice to validate the database-derived observations as well as to suggest potential mechanisms of metformin-mediated aneurysm suppression.Fifty-eight patients met criteria for study inclusion. Of 11 distinct classes of medication considered, only metformin use was negatively associated with AAA enlargement. This association remained significant after controlling for gender, age, cigarette smoking status, and obesity. The median enlargement rate in AAA patients not taking oral diabetic medication was 1.5 mm/y; by nominal logistic regression, metformin, hyperlipidemia, and age ≥70 years were associated with below-median enlargement, whereas sulfonylurea therapy, initial aortic diameter ≥40 mm, and statin use were associated with above-median enlargement. In experimental modeling, metformin dramatically suppressed the formation and progression, with medial elastin and smooth muscle preservation and reduced aortic mural macrophage, CD8 T cell, and neovessel density.Epidemiologic evidence of AAA suppression in diabetes may be attributable to concurrent therapy with the oral hypoglycemic agent metformin.

    View details for DOI 10.1016/j.jvs.2016.02.020

    View details for Web of Science ID 000378562900009

    View details for PubMedID 27106243

    View details for PubMedCentralID PMC4925242

  • Arterial cutdown reduces complications after brachial access for peripheral vascular intervention JOURNAL OF VASCULAR SURGERY Kret, M. R., Dalman, R. L., Kalish, J., Mell, M. 2016; 64 (1): 149-154


    Factors influencing risk for brachial access site complications after peripheral vascular intervention are poorly understood. We queried the Society for Vascular Surgery Vascular Quality Initiative to identify unique demographic and technical risks for such complications.The Vascular Quality Initiative peripheral vascular intervention data files from years 2010 to 2014 were analyzed to compare puncture site complication rates and associations encountered with either brachial or femoral arterial access for peripheral vascular intervention. Procedures requiring multiple access sites were excluded. Complications were defined as wound hematoma or access vessel stenosis/occlusion. Univariate and hierarchical logistic regression was used to identify independent factors associated with site complications after brachial access.Of 44,634 eligible peripheral vascular intervention procedures, 732 (1.6%) were performed through brachial access. Brachial access was associated with an increased complication rate compared with femoral access (9.0% vs 3.3%; P < .001), including more hematomas (7.2% vs 3.0%; P < .001) and access site stenosis/occlusion (2.1% vs 0.4%; P < .001). On univariate analysis, factors associated with brachial access complications included age, female gender, and sheath size. Complications occurred less frequently after arterial cutdown (4.1%) compared with either ultrasound-guided (11.8%) or fluoroscopically guided percutaneous access (7.3%; P = .07 across all variables). Neither surgeons' overall peripheral vascular intervention experience nor prior experience with brachial access predicted likelihood of adverse events. By multivariate analysis, male gender (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.28-0.84; P < .01) and arterial cutdown (OR, 0.25; 95% CI, 0.07-0.87; P = .04) were associated with significantly decreased risk for access complications. Larger sheath sizes (>5F) were associated with increased risk of complications (OR, 2.19; 95% CI, 1.07-4.49; P = .03).Brachial access for peripheral vascular intervention carries significantly increased risks for access site occlusion or hematoma formation. Arterial cutdown and smaller sheath diameters are associated with lower complication rates and thus should be considered when arm access is required.

    View details for DOI 10.1016/j.jvs.2016.02.019

    View details for Web of Science ID 000378562900021

    View details for PubMedID 27021376

  • Unplanned reoperations after vascular surgery. Journal of vascular surgery Kazaure, H. S., Chandra, V., Mell, M. W. 2016; 63 (3): 730-736


    Existing literature on unplanned reoperation (UR) after vascular surgery is limited. The frequency of 30-day UR and its association with other adverse outcomes was analyzed.Patients who underwent vascular procedures in the American College of Surgeons National Surgical Quality Improvement Program (2012) were abstracted. UR, captured by a distinct variable now available in the data set, and its association with complications, readmissions, mortality, and failure to rescue (FTR) were analyzed using bivariate and multivariate methods.Among 35,106 patients, 3545 URs were performed on 2874 patients. The overall UR rate was 10.1%. Among patients who underwent URs, approximately 80.4%, 15.8%, and 3.8% had one, two, and three or more reoperations, respectively; 39.4% of URs occurred after initial discharge. Median time to UR was 7 days but varied by procedure. Procedures with the highest UR rates were embolectomy (18.2%), abdominal bypass (14.4%), and open procedures for peripheral vascular disease (13.8%). Common indications for UR were hemorrhage, graft failure or infection, thromboembolic events, and wound complications. Patients with URs had higher rates of subsequent complications (49.9% vs 19.9%; P < .001), readmission (41.8% vs 7.0%; P < .001), and mortality (8.0% vs 2.5%; P < .001) than those not undergoing URs. FTR was more likely among patients who had a UR (13.6% vs 9.3%; P < .001); this varied within procedure groups. After multivariate adjustment, UR was independently associated with mortality in an incremental fashion (for one UR: adjusted odds ratio, 2.0; 95% confidence interval, 1.7-2.5; for two or more URs: adjusted odds ratio, 3.1; 95% confidence interval, 2.2-4.2).URs within 30 days are frequent among patients undergoing vascular surgery and are associated with worse outcomes, including mortality and FTR.

    View details for DOI 10.1016/j.jvs.2015.09.046

    View details for PubMedID 26553950

  • Discovering the truth about life after discharge: Long-term trauma-related mortality. journal of trauma and acute care surgery Callcut, R. A., Wakam, G., Conroy, A. S., Kornblith, L. Z., Howard, B. M., Campion, E. M., Nelson, M. F., Mell, M. W., Cohen, M. J. 2016; 80 (2): 210-217


    Outcome after traumatic injury has typically been limited to the determination at time of discharge or brief follow-up. This study investigates the natural history of long-term survival after trauma.All highest-level activation patients prospectively enrolled in an ongoing cohort study from 2005 to 2012 were selected. To allow for long-term follow-up, patients had to be enrolled at least 1 year before the latest available data from the National Death Index (NDI, 2013). Time and cause of mortality was determined based on death certificates. Survival status was determined by the latest date of either care in our institution or NDI query. Kaplan-Meier curves were created stratified for Injury Severity Score (ISS). Survival was compared with estimated actuarial survival based on age, sex, and race.A total of 908 highest-level activation patients (median ISS, 18) were followed up for a median 1.7 years (interquartile range 1.0-2.9; maximum, 9.8 years). Survival data were available on 99.8%. Overall survival was 73% (663 of 908). For those with at least 2-year follow-up, survival was only 62% (317 of 509). Severity of injury predicted long-term survival (p < 0.0001) with those having ISS of 25 or greater with the poorest outcome (57% survival at 5 years). For all ISS groups, survival was worse than predicted actuarial survival (p < 0.001). When excluding early deaths (≤30 days), observed survival was still significantly lower than estimated actuarial survival (p < 0.002). Eighteen percent (44 of 245 deaths) of all deaths occurred after 30 days. Among late deaths, 53% occurred between 31 days and 1 year after trauma. Trauma-related mortality was the leading cause of postdischarge death, accounting for 43% of the late deaths.Postdischarge deaths represent a significant percentage of total trauma-related mortality. Despite having "survived" to leave the hospital, long-term survival was worse than predicted actuarial survival, suggesting that the mortality from injury does not end at "successful" hospital discharge.Prognostic study, level III.

    View details for DOI 10.1097/TA.0000000000000930

    View details for PubMedID 26606176

  • Association of an Endovascular-First Protocol for Ruptured Abdominal Aortic Aneurysms With Survival and Discharge Disposition JAMA SURGERY Ullery, B. W., Tran, K., Chandra, V., Mell, M. W., Harris, E. J., Dalman, R. L., Lee, J. T. 2015; 150 (11): 1058-1065
  • Sarcoma Resection With and Without Vascular Reconstruction: A Matched Case-control Study ANNALS OF SURGERY Poultsides, G. A., Tran, T. B., Zambrano, E., Janson, L., Mohler, D. G., Mell, M. W., Avedian, R. S., Visser, B. C., Lee, J. T., Ganjoo, K., Harris, E. J., Norton, J. A. 2015; 262 (4): 632-640


    To examine the impact of major vascular resection on sarcoma resection outcomes.En bloc resection and reconstruction of involved vessels is being increasingly performed during sarcoma surgery; however, the perioperative and oncologic outcomes of this strategy are not well described.Patients undergoing sarcoma resection with (VASC) and without (NO-VASC) vascular reconstruction were 1:2 matched on anatomic site, histology, grade, size, synchronous metastasis, and primary (vs. repeat) resection. R2 resections were excluded. Endpoints included perioperative morbidity, mortality, local recurrence, and survival.From 2000 to 2014, 50 sarcoma patients underwent VASC resection. These were matched with 100 NO-VASC patients having similar clinicopathologic characteristics. The rates of any complication (74% vs. 44%, P = 0.002), grade 3 or higher complication (38% vs. 18%, P = 0.024), and transfusion (66% vs. 33%, P < 0.001) were all more common in the VASC group. Thirty-day (2% vs. 0%, P = 0.30) or 90-day mortality (6% vs. 2%, P = 0.24) were not significantly higher. Local recurrence (5-year, 51% vs. 54%, P = 0.11) and overall survival after resection (5-year, 59% vs. 53%, P = 0.67) were similar between the 2 groups. Within the VASC group, overall survival was not affected by the type of vessel involved (artery vs. vein) or the presence of histology-proven vessel wall invasion.Vascular resection and reconstruction during sarcoma resection significantly increases perioperative morbidity and requires meticulous preoperative multidisciplinary planning. However, the oncologic outcome appears equivalent to cases without major vascular involvement. The anticipated need for vascular resection and reconstruction should not be a contraindication to sarcoma resection.

    View details for DOI 10.1097/SLA.0000000000001455

    View details for Web of Science ID 000367999800009

  • Variability in transfer criteria for patients with ruptured abdominal aortic aneurysm in the western United States JOURNAL OF VASCULAR SURGERY Mell, M. W., Schneider, P. A., Starnes, B. W. 2015; 62 (2): 326-330


    No standards exist for interhospital transfer of patients with ruptured abdominal aortic aneurysm (rAAA). As such, many facilities have developed individual approaches to transfer of these patients. The purpose of this study was to investigate areas of agreement and discord for transfer and to determine if current practices may serve as a starting point for developing universal transfer guidelines.A survey was prepared regarding requirements for transfer, factors regarding transport, and available resources at the accepting hospital. The survey was then offered to members of the Western Vascular Society. Responses were analyzed by physician practice type. Consensus was defined as at least 70% agreement for a response.Response rate was 40%. The cohort comprised 51% from academic institutions and 94% from metropolitan areas. Patients with rAAA were accepted in transfer by 88% of respondents; a majority accepted transfers from distances of up to 100 miles or more. Most had no formal protocol for transfer or treatment of patients with rAAA. Wide variation was observed regarding local evaluation, clinical status at presentation, pre-existing medical comorbidity and required tests for determining suitability for transfer, and management during transport. Academic physicians were more likely to accept clinically unstable patients and to have capability to offer endovascular aneurysm repair.Wide variation was observed regarding clinical suitability for transfer, diagnostic criteria and tests before transfer, and essential resources required at the receiving hospital. Reducing existing variation and inefficiencies in the transfer process by developing standard guidelines may improve population-based outcomes for rAAA.

    View details for DOI 10.1016/j.jvs.2015.03.032

    View details for Web of Science ID 000358431900009

  • Provider Visits and Early Vascular Access Placement in Maintenance Hemodialysis JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Erickson, K. F., Mell, M., Winkelmayer, W. C., Chertow, G. M., Bhattacharya, J. 2015; 26 (8): 1990-1997


    Medicare reimbursement policy encourages frequent provider visits for patients with ESRD undergoing hemodialysis. We hypothesize that patients seen more frequently by their nephrologist or advanced practitioner within the first 90 days of hemodialysis are more likely to undergo surgery to create an arteriovenous (AV) fistula or place an AV graft. We selected 35,959 patients aged ≥67 years starting hemodialysis in the United States from a national registry. We used multivariable regression to evaluate the associations between mean visit frequency and AV fistula creation or graft placement in the first 90 days of hemodialysis. We conducted an instrumental variable analysis to test the sensitivity of our findings to potential bias from unobserved characteristics. One additional visit per month in the first 90 days of hemodialysis was associated with a 21% increase in the odds of AV fistula creation or graft placement during that period (95% confidence interval, 19% to 24%), corresponding to an average 4.5% increase in absolute probability. An instrumental variable analysis demonstrated similar findings. Excluding visits in months when patients were hospitalized, one additional visit per month was associated with a 10% increase in odds of vascular access surgery (95% confidence interval, 8% to 13%). In conclusion, patients seen more frequently by care providers in the first 90 days of hemodialysis undergo earlier AV fistula creation or graft placement. Payment policies that encourage more frequent visits to patients at key clinical time points may yield more favorable health outcomes than policies that operate irrespective of patients' health status.

    View details for DOI 10.1681/ASN.2014050464

    View details for Web of Science ID 000358895100023

    View details for PubMedID 25452668

  • Aortoiliac Elongation after Endovascular Aortic Aneurysm Repair ANNALS OF VASCULAR SURGERY Chandra, V., Rouer, M., Garg, T., Fleischmann, D., Mell, M. 2015; 29 (5): 891-897


    Aortoiliac elongation after endovascular aortic aneurysm repair (EVAR) is not well studied. We sought to assess the long-term morphologic changes after EVAR and identify potentially modifiable factors associated with such a change.An institutional review board-approved retrospective review was conducted for 88 consecutive patients who underwent EVAR at a single academic center from 2003 to 2007 and who also had at least 2 follow-up computed tomography angiograms (CTAs) available for review up to 5 years after surgery. Standardized centerline aortic lengths and diameters were obtained on Aquarius iNtuition 3D workstation (TeraRecon Inc., San Mateo, CA) on postoperative and all-available follow-up CTAs. Relationships to aortic elongation were determined using Wilcoxon rank-sum test or linear regression (Stata version 12.1, College Station, TX). Changes in length over time were determined by mixed-effects analysis (SAS version 9.3, Cary, NC).The study cohort was composed of mostly men (88%), with a mean age of (76 ± 8) and a mean follow-up of 3.2 years (range, 0.4-7.5 years). Fifty-seven percent of patients (n = 50) had devices with suprarenal fixation and 43% (n = 38) had no suprarenal fixation. Significant lengthening was observed over the study period in the aortoiliac segments, but not in the iliofemoral segments. Aortoiliac elongation over time was not associated with sex (P = 0.3), hypertension (P = 0.7), coronary artery disease (P = 0.3), diabetes (P = 0.3), or tobacco use (P = 0.4), but was associated with the use of statins (P = 0.03) and the presence of chronic obstructive pulmonary disease (P = 0.02). Significant aortic lengthening was associated with increased type I endoleaks (P = 0.03) and reinterventions (P = 0.03). Over the study period, 4 different devices were used; Zenith (Cook Medical Inc., Bloomington, IN), Talent (Medtronic, Minneapolis, MN), Aneuryx (Medtronic), and Excluder (W. L. Gore and Associates Inc., Flagstaff, AZ). After adjusting for differences in proximal landing zone, significant differences in aortic lengthening over time were observed by device type (P = 0.02).Significant aortoiliac elongation was observed after EVAR. Such morphologic changes may impact long-term durability of EVAR, warranting further investigation into factors associated with these morphologic changes.

    View details for DOI 10.1016/j.avsg.2014.12.041

    View details for Web of Science ID 000356994400003

    View details for PubMedID 25757989

  • Provider visit frequency and vascular access interventions in hemodialysis. Clinical journal of the American Society of Nephrology Erickson, K. F., Mell, M. W., Winkelmayer, W. C., Chertow, G. M., Bhattacharya, J. 2015; 10 (2): 269-277


    Medicare reimbursement policy encourages frequent provider visits to patients with ESRD undergoing hemodialysis. This study sought to determine whether more frequent face-to-face provider (physician and advanced practitioner) visits lead to more procedures and therapeutic interventions aimed at preserving arteriovenous fistulas and grafts, improved vascular access outcomes, and fewer related hospitalizations.Multivariable regression was used to evaluate the association between provider (physician and advanced practitioner) visit frequency and interventions aimed at preserving vascular access, vascular access survival, hospitalization for vascular access infection, and outpatient antibiotic use in a cohort of 63,488 Medicare beneficiaries receiving hemodialysis in the United States. Medicare claims were used to identify the type of vascular access used, access-related events, and vascular access failure.One additional provider (physician and advanced practitioner) visit per month was associated with a 13% higher odds of receiving an intervention to preserve vascular access (95% confidence interval [95% CI], 12% to 14%) but was not associated with vascular access survival (hazard ratio, 1.01; 95% CI, 0.99 to 1.03). One additional provider visit was associated with a 9% (95% CI, 5% to 14%) lower odds of hospitalization for vascular access infection and a corresponding 9% (95% CI, 5% to 14%) higher odds of outpatient intravenous antibiotic administration. However, the associated changes in absolute probabilities of hospitalization and antibiotic administration were small.More frequent face-to-face provider (physician and advanced practitioner) visits were associated with more procedures and therapeutic interventions aimed at preserving vascular accesses, but not with prolonged vascular access survival and only a small decrease in hospitalization for vascular access.

    View details for DOI 10.2215/CJN.05540614

    View details for PubMedID 25587105

  • Transposition of the left renal vein for the treatment of nutcracker syndrome in children: a short-term experience. Annals of vascular surgery Ullery, B. W., Itoga, N. K., Mell, M. W. 2014; 28 (8): 1938 e5-8


    Nutcracker syndrome is caused by compression of the left renal vein between the superior mesenteric artery and the aorta. Invasive surgical intervention for this pathologic entity is controversial, particularly in the pediatric population. We aim to describe our early clinical and operative experience with such patients.We report 3 cases of pediatric patients undergoing successful left renal vein transposition for the treatment of nutcracker syndrome.All 3 patients were female (age 9-17 years) and presented with a mean of 11.7 months of abdominal or left flank pain requiring chronic narcotic analgesia. Initial clinical presentations were associated with either hematuria or proteinuria. Diagnosis of nutcracker syndrome was supported in each case by an elevated renocaval pressure gradient and/or axial imaging demonstrating mesoaortic compression of the left renal vein. All patients underwent open surgical repair, which included left renal vein transposition, liberation of the ligament of Treitz and associated adhesions, as well as excision of periaortic nodal tissue (mean hospital length of stay 5.7 days). After mean follow-up of 13 months, all patients report complete resolution of symptoms and hematuria/proteinuria.Transposition of the left renal vein is a safe and effective treatment for nutcracker syndrome in appropriately selected pediatric patients. Further experience and long-term follow-up are warranted to better evaluate the sustained efficacy of this procedure in this unique patient population.

    View details for DOI 10.1016/j.avsg.2014.07.022

    View details for PubMedID 25111949

  • Reply: To PMID 24768368. Journal of vascular surgery Mell, M. 2014; 60 (4): 1121-1122

    View details for DOI 10.1016/j.jvs.2014.06.111

    View details for PubMedID 25260479

  • Evaluation of Medicare claims data to ascertain peripheral vascular events in the Women's Health Initiative 37th Annual Meeting of the Midwestern-Vascular-Surgical-Society Mell, M. W., Pettinger, M., Proulx-Burns, L., Heckbert, S. R., Allison, M. A., Criqui, M. H., Hlatky, M. A., Burwen, D. R. MOSBY-ELSEVIER. 2014: 98–105
  • Evaluation of Medicare claims data to ascertain peripheral vascular events in the Women's Health Initiative. Journal of vascular surgery Mell, M. W., Pettinger, M., Proulx-Burns, L., Heckbert, S. R., Allison, M. A., Criqui, M. H., Hlatky, M. A., Burwen, D. R. 2014; 60 (1): 98-105


    Capturing long-term outcomes from large clinical databases by use of claims data is a potential strategy for improving efficiency while reducing study costs. We sought to compare the use of Medicare data with data from the Women's Health Initiative (WHI) to determine peripheral vascular events, as defined by the WHI study design.We studied participants from the WHI with both adjudicated outcomes and links to Medicare enrollment and utilization data through 2007. Outcomes of interest included hospitalizations for treatment of abdominal aortic aneurysm (AAA), lower extremity peripheral artery disease (LE PAD), and carotid artery stenosis (CAS). Events determined by WHI adjudication were compared with events defined by coding algorithms using diagnosis and procedure codes from Medicare data with a pilot data set and then validated with a test data set. We assessed agreement by a κ statistic and evaluated reasons for disagreement.In the pilot set, records from 50,511 participants were analyzed. Agreement between the Centers for Medicare and Medicaid Services and WHI for admissions with a diagnosis but no treatment procedures for vascular conditions was poor (κ, 0.02-0.18). On the basis of WHI outcome data collection, vascular treatment procedures occurred in 29 participants for AAA, 204 for LE PAD events, and 281 for CAS. Medicare hospital claims recorded 41 treatments for AAA, 255 for LE PAD, and 317 for CAS. For participants with a Centers for Medicare and Medicaid Services-captured vascular procedure and a record adjudicated by WHI, κ values for treatment procedures were 0.81 for AAA, 0.77 for PAD, and 0.93 for CAS. For vascular procedures identified by WHI but not by Medicare hospital data (n = 82), 55% were captured by Medicare physician claims. Conversely, for treatments identified by Medicare hospital data but not captured by WHI adjudication (n = 57), 74% had physician claims consistent with the procedure. Fifteen participants with AAA or LE PAD procedures in hospital claims had medical records available for review, and nine of these had definitive documentation of procedures that were not captured by the WHI adjudication process. Estimated positive predictive value of Medicare data was 91% to 94% for AAA, 92% to 95% for LE PAD, and 94% to 99% for CAS. Available test set data (n = 50,253) yielded generally similar results with κ of 0.77 for AAA, 0.79 for LE PAD, and 0.94 for CAS.Medicare data appear useful for identifying vascular treatment procedures for WHI participants. Medicare hospital claims identify more procedures than WHI does, with high positive predictive value, but also may not capture some procedures identified in WHI.

    View details for DOI 10.1016/j.jvs.2014.01.056

    View details for PubMedID 24636641

  • Cost-Effectiveness of Genotype-Guided and Dual Antiplatelet Therapies in Acute Coronary Syndrome ANNALS OF INTERNAL MEDICINE Kazi, D. S., Garber, A. M., Shah, R. U., Dudley, R. A., Mell, M. W., Rhee, C., Moshkevich, S., Boothroyd, D. B., Owens, D. K., Hlatky, M. A. 2014; 160 (4): 221-232
  • Factors impacting follow-up care after placement of temporary inferior vena cava filters 27th Annual Meeting of the Western-Vascular-Society Gyang, E., Zayed, M., Harris, E. J., Lee, J. T., Dalman, R. L., Mell, M. W. MOSBY-ELSEVIER. 2013: 440–45


    Rates of inferior vena cava (IVC) filter retrieval have remained suboptimal, in part because of poor follow-up. The goal of our study was to determine demographic and clinical factors predictive of IVC filter follow-up care in a university hospital setting.We reviewed 250 consecutive patients who received an IVC filter placement with the intention of subsequent retrieval between March 2009 and October 2010. Patient demographics, clinical factors, and physician specialty were evaluated. Multivariate logistic regression analysis was performed to identify variables predicting follow-up care.In our cohort, 60.7% of patients received follow-up care; of those, 93% had IVC filter retrieval. Major indications for IVC filter placement were prophylaxis for high risk surgery (53%) and venous thromboembolic event with contraindication and/or failure of anticoagulation (39%). Follow-up care was less likely for patients discharged to acute rehabilitation or skilled nursing facilities (P < .0001), those with central nervous system pathology (eg, cerebral hemorrhage or spinal fracture; P < .0001), and for those who did not receive an IVC filter placement by a vascular surgeon (P < .0001). In a multivariate analysis, discharge home (odds ratio [OR], 4.0; 95% confidence interval [CI], 1.99-8.2; P < .0001), central nervous system pathology (OR, 0.46; 95% CI, 0.22-0.95; P = .04), and IVC filter placement by the vascular surgery service (OR, 4.7; 95% CI, 2.3-9.6; P < .0001) remained independent predictors of follow-up care. Trauma status and distance of residence did not significantly impact likelihood of patient follow-up.Service-dependent practice paradigms play a critical role in patient follow-up and IVC filter retrieval rates. Nevertheless, specific patient populations are more prone to having poorer rates of follow-up. Such trends should be factored into institutional quality control goals and patient-centered care.

    View details for DOI 10.1016/j.jvs.2012.12.085

    View details for Web of Science ID 000322759500029

    View details for PubMedID 23588109

  • No Difference in Mortality After Inter-Facility Transfer for Patients with Ruptured Abdominal Aortic Aneurysm Mell, M. W., Wang, N. E., Morrison, D. E., Hernandez-Boussard, T. MOSBY-ELSEVIER. 2013: 562–62
  • Late diagnosis of abdominal aortic aneurysms substantiates underutilization of abdominal aortic aneurysm screening for Medicare beneficiaries. Journal of vascular surgery Mell, M. W., Hlatky, M. A., Shreibati, J. B., Dalman, R. L., Baker, L. C. 2013; 57 (6): 1519-1523 e1


    Abdominal aortic aneurysm (AAA) screening remains largely underutilized in the U.S., and it is likely that the proportion of patients with aneurysms requiring prompt treatment is much higher compared with well-screened populations. The goals of this study were to determine the proportion of AAAs that required prompt repair after diagnostic abdominal imaging for U.S. Medicare beneficiaries and to identify patient and hospital factors contributing to early vs late diagnosis of AAA.Data were extracted from Medicare claims records for patients at least 65 years old with complete coverage for 2 years who underwent intact AAA repair from 2006 to 2009. Preoperative ultrasound and computed tomography was tabulated from 2002 to repair. We defined early diagnosis of AAA as a patient with a time interval of greater than 6 months between the first imaging examination and the index procedure, and late diagnosis as patients who underwent the index procedure within 6 months of the first imaging examination.Of 17,626 patients who underwent AAA repair, 14,948 met inclusion criteria. Mean age was 77.5 ± 6.1 years. Early diagnosis was identified for 60.6% of patients receiving AAA repair, whereas 39.4% were repaired after a late diagnosis. Early diagnosis rates increased from 2006 to 2009 (59.8% to 63.4%; P < .0001) and were more common for intact repair compared with repair after rupture (62.9% vs 35.1%; P < .0001) and for women compared with men (66.3% vs 59.0%; P < .0001). On multivariate analysis, repair of intact vs ruptured AAAs (odds ratio, 3.1; 95% confidence interval, 2.7-3.6) and female sex (odds ratio, 1.4; 95% confidence interval, 1.3-1.5) remained the strongest predictors of surveillance. Although intact repairs were more likely to be diagnosed early, over one-third of patients undergoing repair for ruptured AAAs received diagnostic abdominal imaging greater than 6 months prior to surgery.Despite advances in screening practices, significant missed opportunities remain in the U.S. Medicare population for improving AAA care. It remains common for AAAs to be diagnosed when they are already at risk for rupture. In addition, a significant proportion of patients with early imaging rupture prior to repair. Our findings suggest that improved mechanisms for observational management are needed to ensure optimal preoperative care for patients with AAAs.

    View details for DOI 10.1016/j.jvs.2012.12.034

    View details for PubMedID 23414696

  • Implementing Toyota Production System Practices Improves Efficiency of Patient Care in an Academic Vascular Practice Vascular Annual Meeting of the Society-for-Vascular-Surgery (SVS) Mell, M. W., Seshadri, S. B., Kwong, T., Dalman, R. L. MOSBY-ELSEVIER. 2013: 96S–96S
  • Differences in readmissions after open repair versus endovascular aneurysm repair 26th Annual Meeting of the Western-Vascular-Society Casey, K., Hernandez-Boussard, T., Mell, M. W., Lee, J. T. MOSBY-ELSEVIER. 2013: 89–95


    Reintervention rates after repair of abdominal aortic aneurysm (AAA) are higher for endovascular repair (EVAR) than for open repair, mostly due to treatment for endoleaks, whereas open surgical operations for bowel obstruction and abdominal hernias are higher after open repair. However, readmission rates after EVAR or open repair for nonoperative conditions and complications that do not require an intervention are not well documented. We sought to determine reasons for all-cause readmissions within the first year after open repair and EVAR.Patients who underwent elective AAA repair in California during a 6-year period were identified from the Health Care and Utilization Project State Inpatient Database. All patients who had a readmission in California ≤1 year of their index procedure were included for evaluation. Readmission rates and primary and secondary diagnoses associated with each readmission were analyzed and recorded.From 2003 to 2008, there were 15,736 operations for elective AAA repair, comprising 9356 EVARs (60%) and 6380 open repairs (40%). At 1 year postoperatively, the readmission rate was 52.1% after open repair and 55.4% after EVAR (P=.0003). The three most common principle diagnoses associated with readmission after any type of AAA repair were failure to thrive, cardiac issues, and infection. When stratified by repair type, patients who underwent open repair were more likely to be readmitted with primary diagnoses associated with failure to thrive, cardiac complications, and infection compared with EVAR (all P<.001). Those who underwent EVAR were more likely, however, to be readmitted with primary diagnoses of device-related complications (P=.05), cardiac complications, and infection.Total readmission rates within 1 year after elective AAA repair are greater after EVAR than after open repair. Reasons for readmission vary between the two cohorts but are related to the magnitude of open surgery after open repair, device issues after EVAR, and the usual cardiac and infectious complications after either intervention. Systems-based analysis of these causes of readmission can potentially improve patient expectations and care after elective aneurysm repair.

    View details for DOI 10.1016/j.jvs.2012.07.005

    View details for Web of Science ID 000312833800016

    View details for PubMedID 23164606

  • Causes and Implications of Readmission After Abdominal Aortic Aneurysm Repair ANNALS OF SURGERY Greenblatt, D. Y., Greenberg, C. C., Kind, A. J., Havlena, J. A., Mell, M. W., Nelson, M. T., Smith, M. A., Kent, K. C. 2012; 256 (4): 595-605


    To determine the frequency, causes, predictors, and consequences of 30-day readmission after abdominal aortic aneurysm (AAA) repair.Centers for Medicare & Medicaid Services (CMS) will soon reduce total Medicare reimbursements for hospitals with higher-than-predicted 30-day readmission rates after vascular surgical procedures, including AAA repair. However, causes and factors leading to readmission in this population have never before been systematically analyzed.We analyzed elective AAA repairs over a 2-year period from the CMS Chronic Conditions Warehouse, a 5% national sample of Medicare beneficiaries.A total of 2481 patients underwent AAA repair--1502 endovascular aneurysm repair (EVAR) and 979 open aneurysm repair. Thirty-day readmission rates were equivalent for EVAR (13.3%) and open repair (12.8%). Although wound complication was the most common reason for readmission after both procedures, the relative frequency of other causes differed-eg, bowel obstruction was common after open repair, and graft complication after EVAR. In multivariate analyses, preoperative comorbidities had a modest effect on readmission; however, postoperative factors, including serious complications leading to prolonged length of stay and discharge destination other than home, had a profound influence on the probability of readmission. The 1-year mortality in readmitted patients was 23.4% versus 4.5% in those not readmitted (P < 0.001).Early readmission is common after AAA repair. Adjusting for comorbidities, postoperative events predict readmission, suggesting that proactively preventing, detecting, and managing postoperative complications may provide an approach to decreasing readmissions, with the potential to reduce cost and possibly enhance long-term survival.

    View details for DOI 10.1097/SLA.0b013e31826b4bfe

    View details for Web of Science ID 000308917600009

    View details for PubMedID 22964736

  • Predictors of emergency department death for patients presenting with ruptured abdominal aortic aneurysms JOURNAL OF VASCULAR SURGERY Mell, M. W., Callcut, R. A., Bech, F., Delgado, M. K., Staudenmayer, K., Spain, D. A., Hernandez-Boussard, T. 2012; 56 (3): 651-655


    Ruptured abdominal aortic aneurysm (rAAA) is a critically time-sensitive condition with outcomes dependent on rapid diagnosis and definitive treatment. Emergency department (ED) death reflects the hemodynamic stability of the patient upon arrival and the ability to mobilize resources before hemodynamic stability is lost. The goals of this study were to determine the incidence and predictors of ED death for patients presenting to EDs with rAAAs.Data for patients presenting with International Classification of Disease, 9th Revision, Clinical Modification codes for rAAA from 2006 to 2008 were extracted from discharge data using the Nationwide Emergency Department Sample (NEDS), Healthcare Cost and Utilization Project, and Agency for Healthcare Research and Quality. The NEDS is the largest stratified weighted sample of US hospital-based ED visits with links to inpatient files. We compared those transferred to those admitted and treated. Sample weights were applied to produce nationally representative estimates. Patient and hospital factors associated with transfer were identified using multivariate logistic regression. These factors were then analyzed for a relationship with ED deaths.A total of 18,363 patients were evaluated for rAAAs. Of these, 7% (1201) died in the ED, 6% (1160) were admitted and died without a procedure, 42% (7731) were admitted and died after repair, and 41% (7479) were admitted, treated, and survived. Transfers accounted for 4% (793) of all ED visits for rAAAs. ED death was more likely for patients seen in nonmetropolitan hospitals (12.7%) vs metropolitan nonteaching (7.0%) or metropolitan teaching hospitals (4.5%; P < .0001). Compared with other regions, the West had a higher ED mortality rate (9.6% vs 5.1%-6.9%; P = .0038). On multivariate analysis, ED death was associated with hospital groups exhibiting both high and low transfer rates.ED death remains a significant cause for mortality for rAAAs and varies by hospital type, rural/urban location, and geographic region. Both delays in ED arrival and delays in providing definitive care may contribute to increased ED death rates, suggesting that improved regional systems of care may improve survival after rAAA.

    View details for DOI 10.1016/j.jvs.2012.02.025

    View details for Web of Science ID 000308085500010

    View details for PubMedID 22560234

  • Payer status is associated with the use of prophylactic inferior vena cava filter in high-risk trauma patients SURGERY Pickham, D. M., Callcut, R. A., Maggio, P. M., Mell, M. W., Spain, D. A., Bech, F., Staudenmayer, K. 2012; 152 (2): 232-237


    It is controversial whether patients at high risk for pulmonary embolism (PE) should receive prophylactic inferior vena cava filters (IVC) filters. This lack of clarity creates the potential for variability and disparities in care. We hypothesized there would be differential use of prophylactic IVC filters for patients at high risk for PE on the basis of insurance status.We performed a retrospective analysis using the National Trauma Databank (2002-2007). We included adult patients at high risk for PE (traumatic brain injury or spinal cord injury) and excluded patients with a diagnosis of deep venous thrombosis (DVT) or PE. Logistic regression was performed to control for confounders and a hierarchical mixed effects model was used to control for center.A prophylactic filter was placed in 3,331 (4.3%) patients in the study cohort. Patients without insurance had an IVC filter placed less often compared with those with any form of insurance (2.7% vs 4.9%, respectively). After adjusting for confounders, we found that patients without insurance were less likely to receive a prophylactic IVC filter, even when we controlled for center (OR 5.3, P < .001).When guidelines lack clarity, unconscious bias has the potential to create a system with different levels of care based on socioeconomic disparities.

    View details for DOI 10.1016/j.surg.2012.05.041

    View details for Web of Science ID 000307157500013

    View details for PubMedID 22828145

  • Long-term results after accessory renal artery coverage during endovascular aortic aneurysm repair 26th Annual Meeting of the Western-Vascular-Society Greenberg, J. I., Dorsey, C., Dalman, R. L., Lee, J. T., Harris, E. J., Hernandez-Boussard, T., Mell, M. W. MOSBY-ELSEVIER. 2012: 291–97


    Current information regarding coverage of accessory renal arteries (ARAs) during endovascular aneurysm repair (EVAR) is based on small case series with limited follow-up. This study evaluates the outcomes of ARA coverage in a large contemporary cohort.Consecutive EVAR data from January 2004 to August 2010 were collected in a prospective database at a University Hospital. Patient and aneurysm-related characteristics, imaging studies, and ARA coverage versus preservation were analyzed. Volumetric analysis of three-dimensional reconstruction computed tomography scans was used to assess renal infarction volume extent. Long-term renal function and overall technical success of aneurysm exclusion were compared.A cohort of 426 EVARs was identified. ARAs were present in 69 patients with a mean follow-up of 27 months (range, 1 to 60 months). Forty-five ARAs were covered in 40 patients; 29 patients had intentional ARA preservation. Patient and anatomic characteristics were similar between groups except that ARA coverage patients had shorter aneurysm necks (P = .03). Renal infarctions occurred in 84% of kidneys with covered ARAs. There was no significant deterioration in long-term glomerular filtration rate when compared with patients in the control group. No difference in the rate of endoleak, secondary procedures, or the requirement for antihypertensive medications was found.This study is the largest to date with the longest follow-up relating to ARA coverage. Contrary to previous reports, renal infarction after ARA coverage is common. Nevertheless, coverage is well tolerated based upon preservation of renal function without additional morbidity. These results support the long-term safety of ARA coverage for EVAR when necessary.

    View details for DOI 10.1016/j.jvs.2012.01.049

    View details for Web of Science ID 000307160400002

    View details for PubMedID 22480767

  • Factors Impacting Follow-up Care after Placement of Temporary Inferior Vena Cava Filters William J. Von Liebig Forum at the Rapid Session of the Vascular Annual Meeting of the Society-for-Vascular-Surgery (SVS) / Peripheral-Vascular-Surgery-Society Session Gyang, E., Zayed, M., Harris, E. J., Lee, J. T., Dalman, R. L., Mell, M. W. MOSBY-ELSEVIER. 2012: 60–60
  • PANACEA OR PERSONALIZED MEDICINE? OPTIMIZING ANTIPLATELET THERAPY IN ACUTE CORONARY SYNDROME - A COST-EFFECTIVENESS ANALYSIS 61st Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC)/Conference on ACC-i2 with TCT Kazi, D., Garber, A. M., Shah, R., Rhee, C., Moshkevich, S., Mell, M. W., Boothroyd, D., Owens, D. K., Hlatky, M. ELSEVIER SCIENCE INC. 2012: E348–E348
  • Is the "lipid paradox" in rheumatoid arthritis really a paradox? Comment on the article by Bartels et al Reply ARTHRITIS AND RHEUMATISM Bartels, C. M., Everett, C., McBride, P., Smith, M., Kind, A. J., Mell, M. 2011; 63 (11): 3645-3646

    View details for DOI 10.1002/art.30587

    View details for Web of Science ID 000297221100061

  • Predictors of surgical site infection after open lower extremity revascularization 38th Annual Symposium of the Society-for-Clinical-Vascular-Surgery Greenblatt, D. Y., Rajamanickam, V., Mell, M. W. MOSBY-ELSEVIER. 2011: 433–39


    Surgical site infection (SSI) after open surgery for lower extremity revascularization is a serious complication that may lead to graft infection, prolonged hospitalization, and increased cost. Rates of SSI after revascularization vary widely, with most studies reported from single institutions. The objective of this study was to describe the rate and predictors of SSI after surgery for arterial occlusive disease using national data, and to identify any association between SSI and length of hospital stay, reoperation, graft loss, and mortality.Patients who underwent lower extremity arterial bypass or thromboendarterectomy from 2005-2008 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) participant use files. Multivariate logistic regression identified predictors of SSI. Odds ratios were adjusted for patient demographics, comorbidities, preoperative laboratory values, and operative factors. The association between SSI and other 30-day outcomes such as mortality and graft failure was determined.Of 12,330 patients who underwent revascularization, 1367 (11.1%) were diagnosed with an SSI within 30 days. Multivariate predictors of SSI included female gender (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.3-1.6), obesity (OR, 2.1; 95% CI, 1.8-2.4), chronic obstructive pulmonary disease (OR, 1.2; 95% CI, 1.0-1.5), dialysis (OR, 1.5; 95% CI, 1.1-2.1), preoperative hyponatremia (OR, 1.2; 95% CI, 1.0-1.4), and length of operation >4 hours (OR, 1.4; 95% CI, 1.2-1.6). SSI was associated with prolonged (>10 days) hospital stay (OR, 1.8; 95% CI, 1.4-2.1) and higher rates of 30-day graft loss (OR, 2.3; 95% CI, 1.7-3.1) and reoperation (OR, 3.7; 95% CI, 3.1-4.6). SSI was not associated with increased 30-day mortality.SSI is a common complication after open revascularization and is associated with a more than twofold increased risk of early graft loss and reoperation. Several patient and operation-related risk factors that predict postoperative SSI were identified, suggesting that targeted improvements in perioperative care may decrease complications and improve outcomes in this patient population.

    View details for DOI 10.1016/j.jvs.2011.01.034

    View details for Web of Science ID 000293814400026

    View details for PubMedID 21458203

  • Under-Utilization of Transfer for Ruptured Abdominal Aortic Aneurysm (rAAA) in the Western United States Mell, M. W., Callcut, R. A., Bech, F., Delgado, K., Staudenmayer, K., Spain, D. A., Hernandez-Boussard, T. MOSBY-ELSEVIER. 2011: 590–91
  • Readmissions after Abdominal Aortic Aneurysm Repair: Differences between Open Repair and Endovascular Aneurysm Repair Casey, K. M., Hernandez-Boussard, T., Al-Khatib, W. K., Mell, M. W., Lee, J. T. MOSBY-ELSEVIER. 2011: 590–90
  • Long-Term Results after Accessory Renal Artery Coverage during Endovascular Aortic Aneurysm Repair Greenberg, J. I., Dorsey, C., Dalman, R. L., Lee, J. T., Mell, M. W. MOSBY-ELSEVIER. 2011: 588–88
  • No Increased Mortality with Early Aortic Aneurysm Disease Mell, M., White, J. J., Hill, B. B., Dalman, R. L. MOSBY-ELSEVIER. 2011: 591–91
  • Failure to rescue and mortality after reoperation for abdominal aortic aneurysm repair 25th Annual Meeting of the Western-Vascular-Society Mell, M. W., Kind, A., Bartels, C. M., Smith, M. A. MOSBY-ELSEVIER. 2011: 346–51


    Complications after abdominal aortic aneurysm (AAA) repair resulting in reintervention increase mortality risk, but have not been well studied. Mortality after reintervention is termed failure to rescue and may reflect differences related to quality management of the complication. This study describes the relationship between reoperation and mortality and examines the effect of physician speciality on reintervention rates and failure to rescue after AAA repair.Data were extracted for 2616 patients who underwent intact AAA repair in 2005 to 2006 from a standard 5% random sample of all Medicare beneficiaries. Patient demographics, comorbidities, hospital characteristics, repair type, and speciality of operating surgeon were collected. Primary outcomes were 30-day reoperation and 30-day mortality. Logistic regression analysis identified characteristics predicting reoperation.A total of 156 reoperations were required in 142 (4.2%) patients. Early mortality was far more likely for patients requiring reintervention than for those who did not (22.5% vs 1.5%; P < .0001). Of patients requiring reoperation, those requiring two or more interventions had an even higher mortality (54% vs 20%; P = .0007). Despite equivalent reoperation rates between specialities (vascular surgeons, 5.2%; others, 5.6%, P = .67), the mortality after reoperation was nearly half for vascular surgeons compared with other specialities (16.2% vs 32.3%; P = .04). The most common reason for reoperation was arterial complications (35.8%) accounting for the largest difference in mortality between vascular surgeons (30.7%) and other specialities (52.0%).Postoperative complications requiring reoperation dramatically increase mortality after AAA repair. Despite similar complication rates, vascular surgeons showed lower mortality rates after reoperation.

    View details for DOI 10.1016/j.jvs.2011.01.030

    View details for Web of Science ID 000293814400012

    View details for PubMedID 21498030

  • Low Frequency of Primary Lipid Screening Among Medicare Patients With Rheumatoid Arthritis ARTHRITIS AND RHEUMATISM Bartels, C. M., Kind, A. J., Everett, C., Mell, M., McBride, P., Smith, M. 2011; 63 (5): 1221-1230


    Although studies have demonstrated suboptimal preventive care in RA patients, performance of primary lipid screening (i.e., testing before cardiovascular disease [CVD], CVD risk equivalents, or hyperlipidemia is evident) has not been systematically examined. The purpose of this study was to examine associations between primary lipid screening and visits to primary care providers (PCPs) and rheumatologists among a national sample of older RA patients.This retrospective cohort study examined a 5% Medicare sample that included 3,298 RA patients without baseline CVD, diabetes mellitus, or hyperlipidemia, who were considered eligible for primary lipid screening during the years 2004-2006. The outcome was probability of lipid screening by the relative frequency of primary care and rheumatology visits, or seeing a PCP at least once each year.Primary lipid screening was performed in only 45% of RA patients. Overall, 65% of patients received both primary and rheumatology care, and 50% saw a rheumatologist as often as a PCP. Any primary care predicted more lipid screening than lone rheumatology care (26% [95% confidence interval (95% CI) 21-32]). As long as a PCP was involved, performance of lipid screening was similar regardless of the balance between primary and rheumatology visits (44-48% [95% CI 41-51]). Not seeing a PCP at least annually decreased screening by 22% (adjusted risk ratio 0.78 [95% CI 0.71-0.84]).Primary lipid screening was performed in fewer than half of eligible RA patients, highlighting a key target for CVD risk reduction efforts. Annual visits to a PCP improved lipid screening, although performance remained poor (51%). Half of RA patients saw their rheumatologist as often or more often than they saw a PCP, illustrating the need to study optimal partnerships between PCPs and rheumatologists for screening patients for CVD risks.

    View details for DOI 10.1002/art.30239

    View details for Web of Science ID 000290609800009

    View details for PubMedID 21305507

  • For-Profit Hospital Status and Rehospitalizations at Different Hospitals: An Analysis of Medicare Data ANNALS OF INTERNAL MEDICINE Kind, A. J., Bartels, C., Mell, M. W., Mullahy, J., Smith, M. 2010; 153 (11): 718-W242


    About one quarter of rehospitalized Medicare patients are admitted to hospitals different from their original hospital. The extent to which this practice is related to for-profit hospital status and affects payments and mortality is unknown.To describe and examine predictors of and payments for rehospitalization at a different hospital among Medicare patients rehospitalized within 30 days at for-profit and nonprofit or public hospitals.Cohort study of patients discharged and rehospitalized from January 2005 to November 2006.Medicare fee-for-service hospitals throughout the United States.A 5% random national sample of Medicare patients with acute care rehospitalizations within 30 days of discharge (n = 74,564).30-day rehospitalizations at different hospitals and total payments or mortality over the subsequent 30 days. Multivariate logistic and quantile regression models included index hospital for-profit status, discharge counts, geographic region, rural-urban commuting area, and teaching status; patient sociodemographic characteristics, disability status, and comorbid conditions; and a measure of risk adjustment.16 622 patients (22%) in the sample were rehospitalized at a different hospital. Factors associated with increased risk for rehospitalization at a different hospital included index hospitalization at a for-profit, major medical school-affiliated, or low-volume hospital and having a Medicare-defined disability. Compared with patients rehospitalized at the same hospital, patients rehospitalized at different hospitals had higher adjusted 30-day total payments (median additional cost, $1308 per patient; P < 0.001) but no statistically significant differences in 30-day mortality, regardless of index hospital for-profit status.The database lacked detailed clinical information about patients and did not include information about specific provider practice motivations or the role of patient choice in hospitalization venues.Rehospitalizations at different hospitals are common among Medicare patients, are more likely among those initially hospitalized at a for-profit hospital, and are related to increased overall payments without improved mortality.University of Wisconsin Hartford Center of Excellence in Geriatrics, National Institutes of Health.

    View details for DOI 10.1059/0003-4819-153-11-201012070-00005

    View details for Web of Science ID 000285003800004

    View details for PubMedID 21135295

  • Effect of early plasma transfusion on mortality in patients with ruptured abdominal aortic aneurysm SURGERY Mell, M. W., O'Neil, A. S., Callcut, R. A., Acher, C. W., Hoch, J. R., Tefera, G., Turnipseed, W. D. 2010; 148 (5): 955-962


    The ratio of red blood cell (PRBC) transfusion to plasma (FFP) transfusion (PRBC:FFP ratio) has been shown to impact survival in trauma patients with massive hemorrhage. The purpose of this study was to determine the effect of the PRBC:FFP ratio on mortality for patients with massive hemorrhage after ruptured abdominal aortic aneurysm (RAAA).A retrospective review was performed of patients undergoing emergent open RAAA repair from January 1987 to December 2007. Patients with massive hemorrhage (≥10 units of blood products transfused prior to conclusion of the operation) were included. The effects of patient demographics, admission vital signs, laboratory values, peri-operative variables, amount of blood products transfused, and the PRBC:FFP ratio on 30-day mortality were analyzed by multivariate analysis.One hundred and twenty-eight of the 168 (76%) patients undergoing repair for RAAA received at least 10 units of blood products within the peri-operative period. Mean age was 73.1 ± 9.1 years, and 109 (85%) were men. Thirty-day mortality was 22.6% (29/128), including 11 intra-operative deaths. By multivariate analysis, 30-day mortality was markedly lower (15% vs 39%; P < .03) for patients transfused at a PRBC:FFP ratio ≤2:1 (HIGH FFP group) compared with those transfused at a ratio of >2:1 (LOW FFP), and the likelihood of death was more than 4-fold greater in the LOW FFP group (odds ratio 4.23; 95% confidence interval, 1.2-14.49). Patients in the HIGH FFP group had a significantly lower incidence of colon ischemia than those in the LOW FFP group (22.4% vs 41.1%; P = .004).For RAAA patients requiring massive transfusion, more equivalent transfusion of PRBC to FFP (HIGH FFP) was independently associated with lower 30-day mortality. The lower incidence of colonic ischemia in the HIGH FFP group may suggest an additional benefit of early plasma transfusion that could translate into further mortality reduction. Analysis from this study suggests the potential feasibility for a more standardized protocol of initial resuscitation for these patients, and prospective studies are warranted to determine the optimum PRBC:FFP ratio in RAAA patients.

    View details for DOI 10.1016/j.surg.2010.02.002

    View details for Web of Science ID 000283888000008

    View details for PubMedID 20378142

  • Failure to Rescue: Physician Specialty and Mortality After Reoperation for Abdominal Aortic Aneurysm (AAA) Repair 25th Annual Meeting of the Western-Vascular-Society Mell, M. W., Kind, A., Bartels, C. M., Smith, M. A. MOSBY-ELSEVIER. 2010: 528–28
  • Presurgical Localization of the Artery of Adamkiewicz with Time-resolved 3.0-T MR Angiography RADIOLOGY Bley, T. A., Duffek, C. C., Francois, C. J., Schiebler, M. L., Acher, C. W., Mell, M., Grist, T. M., Reeder, S. B. 2010; 255 (3): 873-881


    To evaluate the use of time-resolved magnetic resonance (MR) angiography in the presurgical localization of the artery of Adamkiewicz prior to reimplantation of the feeding intercostal artery, lumbar artery, or both during aortic aneurysm repair.This institutional review board-approved retrospective study included 68 patients (36 men, 32 women) who underwent time-resolved spinal MR angiography (0.2 mmol per kilogram of body weight gadobenate dimeglumine administered at a rate of 2.0 mL per second) performed with a 3.0-T imager with a dedicated eight-element spine coil. Images were reviewed at a three-dimensional workstation by two experienced radiologists in consensus. The artery of Adamkiewicz was identified, and the location of the feeding intercostal and/or lumbar artery was ascertained by using a five-point confidence index (scores ranged from 1 to 5). The phases in which the artery of Adamkiewicz, aorta, and great anterior radiculomedullary vein (GARV) demonstrated peak enhancement were also recorded.The artery of Adamkiewicz and the location of the feeding intercostal and/or lumbar artery were identified with high confidence in 60 (88%) of the 68 patients. Origins of the artery of Adamkiewicz were on the left side of the body in 65% of patients and on the right side in 35%. The level of origin ranged from the T6 neuroforamina to the L1 neuroforamina. The arrival of contrast material was highly variable in this patient population, which had substantial aortic disease. The highest signal intensity in the aorta, artery of Adamkiewicz, and GARV occurred a mean of 55 seconds (range, 27-99 seconds; 95% confidence interval [CI] 51, 58), 72 seconds (range, 38-110 seconds; 95% CI: 68, 76), and 95 seconds (range, 46-156 seconds; 95% CI: 89, 101) after contrast material administration, respectively.The artery of Adamkiewicz and the anterior spinal artery can be identified and differentiated from the GARV even in patients with substantially altered hemodynamics by using time-resolved 3.0-T MR angiography.

    View details for DOI 10.1148/radiol.10091304

    View details for Web of Science ID 000278038500027

    View details for PubMedID 20501724

  • Impact of Intraoperative Arteriography on Limb Salvage for Traumatic Popliteal Artery Injury 66th Annual Meeting of the American-Association-for-the-Surgery-of-Trauma Callcut, R. A., Acher, C. W., Hoch, J., Tefera, G., Turnipseed, W., Mell, M. W. LIPPINCOTT WILLIAMS & WILKINS. 2009: 252–57


    Time to revascularization is speculated to be a major determinant of limb salvage for traumatic popliteal injuries. The purpose of this study was to determine whether location of diagnostic arteriography affected outcome.From 1996 to 2006, patients with popliteal injuries were identified from our trauma database. Additional data were extracted from chart review. Amputation rates for those undergoing arteriography performed in radiology (ARAD) versus the operating room (AOR) were compared.In 35 patients 36 limbs were treated, with 94% resulting from blunt mechanisms. The mean age was 37 years (11-69 years), 81% were men, and the mean Injury Severity Score was 15. The average mangled extremity severity scores (MESS) was 6 +/- 2. Follow-up was available in 97% patients with a median of 14 months. Overall amputation rate was 16.7% (6 of 36). Extremities with MESS <8 had 93% limb salvage, and MESS > or =8 had 55% limb salvage. ARAD (n = 10) and AOR (n = 15) groups were equivalent with regard to age, mechanism, Injury Severity Score, MESS, time to presentation, associated injuries, and fasciotomy rate. The median time from emergency room arrival to operating room was shorter (125 minutes vs. 214 minutes; p < 0.05) and salvage rate was higher (100% vs. 70%; p = 0.05) in the AOR group compared with the ARAD group.For popliteal artery injuries, diagnostic arteriography in the operating room reduces the likelihood of amputation by decreasing time to initiating repair and thereby limiting limb ischemia. Salvage is possible in the most severely injured extremities with rapid transport to the operating room.

    View details for DOI 10.1097/TA.0b013e31819ea796

    View details for Web of Science ID 000268898500008

    View details for PubMedID 19667876

  • A New Intercostal Artery Management Strategy for Thoracoabdominal Aortic Aneurysm Repair JOURNAL OF SURGICAL RESEARCH Mell, M. W., Wynn, M. M., Reeder, S. B., Tefera, G., Hoch, J. R., Acher, C. W. 2009; 154 (1): 99-104


    The purpose of this study is to describe a new approach for addressing the intraoperative management of intercostal arteries during thoracoabdominal aortic aneurysm (TAAA) repair, using preoperative spinal MRA for detection of intercostal arteries supplying the anterior spinal artery.Patients undergoing TAAA repair from August 2005 to September 2007 were included. Spinal artery MRA was performed to identify the anterior spinal artery, the artery of Adamkiewicz, and its major intercostal source artery (SA-AAK). Intraoperative spinal cord protection was carried out using standard techniques. Important intercostal arteries were either preserved or reimplanted as a button patch after removing aortic clamps. Demographic and perioperative data were collected for review. Analysis was performed with Fisher's exact test or Student's t-test, where applicable, using SAS ver. 8.0 (Cary, NC).Spinal artery MRA was performed in 27 patients. The SA-AAK was identified in 85% of preoperative studies. Open or endovascular repair was performed in 74% and 26% of patients, respectively. The SA-AAK was preserved or reimplanted in 13 (65%) of patients who underwent open repair. A mean of 1.67 (range 1-3) intercostal arteries were reimplanted. All patients undergoing endovascular repair necessitated coverage of the SA-AAK. No patient developed immediate or delayed paraplegia. Longer mean operative times in the reimplanted cohort were not statistically significant (330 versus 245 min, P = 0.1).The SA-AAK identified by MRA can be preserved or safely reimplanted after TAAA repair. Further study is warranted to determine if selective intercostal reimplantation can reduce the risk of immediate or delayed paraplegia.

    View details for DOI 10.1016/j.jss.2008.05.024

    View details for Web of Science ID 000266080000015

    View details for PubMedID 19101698

  • Adult-Onset Dysphagia Lusoria from an Uncommon Vascular Ring: A Case Report and Review of the Literature VASCULAR AND ENDOVASCULAR SURGERY Sitzman, T. J., Mell, M. W., Acher, C. W. 2009; 43 (1): 100-102


    Vascular rings are a rare cause of symptoms in adult patients. We report the case of a 48-year-old woman presenting with dysphagia lusoria due to an uncommon vascular ring: right aortic arch with mirror-image branching and a left ligamentum arteriosum. No previous reports exist of adult-onset dysphagia lusoria attributable to this anatomy. The patient underwent a limited muscle-sparing thoracotomy with division of the ligamentum. The division interrupted the vascular ring and relieved her esophageal compression. The presentation, evaluation, pathophysiology, and treatment of this condition are discussed.

    View details for DOI 10.1177/1538574408323503

    View details for Web of Science ID 000263636400014

    View details for PubMedID 18829585

  • Complications of spinal fluid drainage in thoracoabdominal aortic aneurysm repair: A report of 486 patients treated from 1987 to 2008 62nd Annual Meeting of the Society-for-Vascular-Surgery Wynn, M. M., Mell, M. W., Tefera, G., Hoch, J. R., Acher, C. W. MOSBY-ELSEVIER. 2009: 29–35


    Spinal fluid drainage reduces paraplegia risk in thoracic (TAA) and thoracoabdominal (TAAA) aortic aneurysm repair. There has not been a comprehensive study of the risks of spinal fluid drainage and how these risks can be reduced. Here we report complications of spinal fluid drainage in patients undergoing TAA/TAAA repair.The study comprised 648 patients who had TAA or TAAA repair from 1987 to 2008. Spinal drains were used in 486 patients. Spinal fluid pressure was measured continuously, except when draining fluid, and was reduced to <6 mm Hg during thoracic aortic occlusion and reperfusion. After surgery, spinal fluid pressure was kept <10 mm Hg until patients were awake with normal leg lift. Drains were removed 48 hours after surgery. Spinal and head computed tomography (CT) scans were performed in patients with bloody spinal fluid or neurologic deficit. We studied the incidence of headache treated with epidural blood patch, infection, bloody spinal fluid, intracranial and spinal bleeding on CT, as well as the clinical consequences.Twenty-four patients (5%) had bloody spinal fluid. CT exams showed seven had no evidence of intracranial hemorrhage, 14 (2.9%) had intracranial blood without neurologic deficit, and three with intracranial bleeding and cerebral atrophy had neurologic deficits (1 died, 1 had permanent hemiparesis, and 1 with transient ataxia recovered fully). Two patients without bloody spinal fluid or neurologic deficit after surgery presented with neurologic deficits 5 days postoperatively and died from acute on chronic subdural hematoma. Neurologic deficits occurred after spinal fluid drainage in 5 of 482 patients (1%), and 3 died. The mortality from spinal fluid drainage complications was 0.6% (3 of 482). By univariate and multivariate analysis, larger volume of spinal fluid drainage (mean, 178 mL vs 124 mL, P < .0001) and higher central venous pressure before thoracic aortic occlusion (mean, 16 mm Hg vs 13 mm Hg, P < .0012) correlated with bloody spinal fluid.Strategies that reduce the volume of spinal fluid drainage but still control spinal fluid pressure are helpful in reducing serious complications. Patients with cerebral atrophy are at increased risk for complications of spinal fluid drainage.

    View details for DOI 10.1016/j.jvs.2008.07.076

    View details for Web of Science ID 000262547800006

    View details for PubMedID 18951749

  • Outcomes after endarterectomy for chronic mesenteric ischemia JOURNAL OF VASCULAR SURGERY Mell, M. W., Acher, C. W., Hoch, J. R., Tefera, G., Turnipseed, W. D. 2008; 48 (5): 1132-1138


    A retrospective study was performed to identify optimal factors affecting outcomes after open revascularization for chronic mesenteric ischemia.All patients who underwent open surgery for chronic mesenteric ischemia from 1987 to 2006 were reviewed. Patients with acute mesenteric ischemia or median arcuate ligament syndrome were excluded. Mortality, recurrent stenosis, and symptomatic recurrence were analyzed using logistic regression, and univariate and multivariate analysis.We identified 80 patients (69% women, 31% men). Mean age was 64 years (range, 31-86 years). Acute-on-chronic symptoms were present in 26%. Presenting symptoms included postprandial pain (91%), weight loss (69%), and food fear and diarrhea (25%). Preoperative imaging demonstrated severe (>70%) stenosis of the superior mesenteric artery in 75 patients (24 occluded), the celiac axis in 63 (20 occluded), and the inferior mesenteric artery in 53 (20 occluded). Multivessel disease was present in 72 patients (90%), and 40 (50%) underwent multivessel reconstruction. Revascularization was achieved by endarterectomy in 37 patients, mesenteric bypass in 29, and combined procedures in 14. Concurrent aortic reconstruction was required in 13 patients (16%). Three hospital deaths occurred (3.8%). Mean follow-up was 3.8 years (range, 0-17.2 years). One- and 5-year survival was 92.2% and 64.5%. Mortality was associated with age (P = .019) and renal insufficiency (P = .007), but not by clinical presentation. Symptom-free survival was 89.7% and 82.1% at 1 and 5 years, respectively. Symptoms requiring reintervention occurred in nine patients (11%) at a mean of 29 months (range, 5-127 months). Multivariate analysis showed that freedom from recurrent symptoms correlated with endarterectomy for revascularization (5.2% vs 27.6%; hazard ratio, 0.20; 95% confidence interval, 0.04-0.92; P = .02).For open surgical candidates, endarterectomy appears to provide the most durable long-term symptom relief in patients with chronic mesenteric ischemia.

    View details for DOI 10.1016/j.jvs.2008.06.033

    View details for Web of Science ID 000260725300010

    View details for PubMedID 18771889

  • A Quantitative Assessment of the Impact of Intercostal Artery Reimplantation on Paralysis Risk in Thoracoabdominal Aortic Aneurysm Repair ANNALS OF SURGERY Acher, C. W., Wynn, M. M., Mell, M. W., Tefera, G., Hoch, J. R. 2008; 248 (4): 529-538


    We previously demonstrated an 80% reduction in paraplegia risk using hypothermia, naloxone, steroids, spinal fluid drainage, intercostal ligation, and optimizing hemodynamic parameters. This report demonstrates that intercostal revascularization for the last 3 years further reduced our paraplegia risk index by 75%.We evaluated 655 patients who had thoracic or thoracoabdominal aneurysm repair for factors that affected paraplegia risk including aneurysm extent, acuity, cardiac function, blood pressure mean arterial pressure, and spinal fluid drainage with naloxone (SFDN). Eighteen patients died during or shortly after surgery leaving 637 patients for analysis of paralysis. We evaluated the effect of intercostal reimplantation (IRP) using a highly accurate (r(2) > 0.88) paraplegia risk index we developed and published previously.Fifty-eight percent of patients were male with a mean age of 67. Thirty-three percent were acute with rupture, acute dissection, mycotic aortitis, and trauma. Eighty (12%) had dissections. Thirty-five patients had paraplegia or paraparesis (5.4%). Significant factors by univariate analysis (P < 0.05) were Crawford type 2, acuity, SFDN, cardiac index after unclamping, mean arterial pressure during crossclamping, and IRP. In multivariate modeling, aneurysm extent, SFDN, acuity, and IRP remained significant (P < 0.02). The paraplegia risk index declined from 0.20 to 0.05 (P < 0.03).The incidence of paralysis after TAAA repair decreased from 4.83% to 0.88% and paralysis risk index decreased from 0.26 to 0.05 when intercostal artery reimplantation was added to neuroprotective strategies that had already substantially reduced paralysis risk. These findings suggest that factors that affect collateral blood flow and metabolism account for approximately 80% of paraplegia risk and intercostal blood flow accounts for 20% of risk. This suggests a limit to paraplegia risk reduction in thoracoabdominal endograft patients. Early results in this emerging field support this prediction of high paraplegia risk with thoracoabdominal branched endografts with extensive aortic coverage.

    View details for DOI 10.1097/SLA.0b013e318187a792

    View details for Web of Science ID 000260483700006

    View details for PubMedID 18936565

  • Effectiveness of intensive medical therapy in type B aortic dissection: A single-center experience 30th Annual Meeting of the Midwestern-Vascular-Surgical-Society Tefera, G., Acher, C. W., Hoch, J. R., Mell, M., Turnipseed, W. D. MOSBY-ELSEVIER. 2007: 1114–18


    Although the mainstay of managing acute descending thoracic aortic dissection (ADTAD) remains medical, certain patients will require emergency surgery for complications of rupture or ischemia. This study evaluates factors that affect outcome and determines which patients previously treated surgically would have been eligible for endovascular repair.A single-institution retrospective study was conducted of patients who presented with clinical signs of ADTAD that was confirmed by magnetic resonance angiography (MRA) or computed tomography (CT). All patients were admitted to the intensive care unit (ICU) and medically managed to maintain systolic blood pressure<120 mm Hg and heart rate<70 beats/min. Two treatment groups were identified: group 1 received medical treatment only; group 2 received medical treatment plus emergency surgery. Patient demographic and clinical data were correlated with 30-day group mortality and morbidity and need for emergency surgery. The MRA and CT scan images of group 2 were retrospectively reviewed to determine if currently available endovascular treatment could have been done. The Fisher exact test was used to compare between the groups, and P<.05 was considered significant.Between 1991 and 2005, 83 patients (55 men) were treated for ADTAD. The mean age was 67 years (range, 38 to 85). Sixty-eight patients (82%) had hypertension, three (3.6%) had Marfan syndrome, and 51 (62%) were smokers. Twenty-five (32%) of the patients were receiving beta-blocker therapy before the onset of their symptoms. Back pain was the most common initial symptom (72.2%). Emergency surgery was required in 19 patients (23%): 12 for rupture or impending rupture, four for mesenteric ischemia, and three for lower extremity ischemia. The need for emergency surgery was significantly higher in smokers (P=.03), in patients>70 years old (P=.035), and in patients who were not receiving beta-blocker therapy before the onset of symptoms (P=.023). The combined overall morbidity rate was 33%, and the mortality rate was 9.6%. Morbidity in group 2 was 64% and significantly higher than the 23% in group 1 (P=.00227). The mortality rate was also higher in group 2 at 31.5% compared with group 1 at 1.6% (P=.0004). Factors affecting the overall mortality included age>70 years (P=.057), previous abdominal aortic aneurysm repair (P=.018), tobacco use (P=.039), and the presence of leg pain at initial presentation (P=.013). As determined from the review of radiologic data, 11 of 13 patients with scans available for review in group 2 could have been treated with currently available endovascular grafts.Intensive medical therapies are effective in preventing early mortality associated with ADTAD. Predictably, the need for emergency surgery carries a high morbidity and mortality rate. Most patients in this series requiring emergency surgery could have been candidates for endovascular therapy had it been available.

    View details for DOI 10.1016/j.jvs.2007.01.065

    View details for Web of Science ID 000246931500004

    View details for PubMedID 17543672

  • Clinical utility of time-resolvcd imaging of contrast kinetics (TRICK-S) magnetic resonance angiography for infrageniculate arterial occlusive disease 30th Annual Meeting of the Midwestern-Vascular-Surgical-Society Mell, M., Tefera, G., Thornton, F., Siepman, D., Turnipseed, W. MOSBY-ELSEVIER. 2007: 543–48


    The diagnostic accuracy of magnetic resonance angiography (MRA) in the infrapopliteal arterial segment is not well defined. This study evaluated the clinical utility and diagnostic accuracy of time-resolved imaging of contrast kinetics (TRICKS) MRA compared with digital subtraction contrast angiography (DSA) in planning for percutaneous interventions of popliteal and infrapopliteal arterial occlusive disease.Patients who underwent percutaneous lower extremity interventions for popliteal or tibial occlusive disease were identified for this study. Preprocedural TRICKS MRA was performed with 1.5 Tesla (GE Healthcare, Waukesha, Wis) magnetic resonance imaging scanners with a flexible peripheral vascular coil, using the TRICKS technique with gadodiamide injection. DSA was performed using standard techniques in angiography suite with a 15-inch image intensifier. DSA was considered the gold standard. The MRA and DSA were then evaluated in a blinded fashion by a radiologist and a vascular surgeon. The popliteal artery and tibioperoneal trunk were evaluated separately, and the tibial arteries were divided into proximal, mid, and distal segments. Each segment was interpreted as normal (0% to 49% stenosis), stenotic (50% to 99% stenosis), or occluded (100%). Lesion morphology was classified according to the TransAtlantic Inter-Society Consensus (TASC). We calculated concordance between the imaging studies and the sensitivity and specificity of MRA. The clinical utility of MRA was also assessed in terms of identifying arterial access site as well as predicting technical success of the percutaneous treatment.Comparisons were done on 150 arterial segments in 30 limbs of 27 patients. When evaluated by TASC classification, TRICKS MRA correlated with DSA in 83% of the popliteal and in 88% of the infrapopliteal segments. MRA correctly identified significant disease of the popliteal artery with a sensitivity of 94% and a specificity of 92%, and of the tibial arteries with a sensitivity of 100% and specificity of 84%. When used to evaluate for stenosis vs occlusion, MRA interpretation agreed with DSA 90% of the time. Disagreement occurred in 15 arterial segments, most commonly in distal tibioperoneal arteries. MRA misdiagnosed occlusion for stenosis in 11 of 15 segments, and stenosis for occlusion in four of 15 segments. Arterial access was accurately planned based on preprocedural MRA findings in 29 of 30 patients. MRA predicted technical success 83% of the time. Five technical failures were due to inability to cross arterial occlusions, all accurately identified by MRA.TRICKS MRA is an accurate method of evaluating patients for popliteal and infrapopliteal arterial occlusive disease and can be used for planning percutaneous interventions.

    View details for DOI 10.1016/j.jvs.2006.11.045

    View details for Web of Science ID 000244547900021

    View details for PubMedID 17223303

  • Absence of buttock claudication following stent-graft coverage of the hypogastric artery without coil embolization in endovascular aneurysm repair JOURNAL OF ENDOVASCULAR THERAPY Mell, M., Tefera, G., Schwarze, M., Carr, S., Acher, C., Hoch, J., Turnipseed, W. 2006; 13 (3): 415-419


    To evaluate the safety and efficacy of stent-graft coverage of the hypogastric artery origin without coil embolization during endovascular treatment of aortoiliac or iliac aneurysms.A retrospective study was conducted of patients who underwent endovascular aneurysm repair with endograft coverage of the hypogastric artery between September 2001 and September 2005. Among the 88 patients who underwent EVAR during the study period, 21 patients (19 men; mean age 77+/-6 years, range 67-86) had unilateral hypogastric artery coverage without coil embolization. Aneurysmal arteries included 11 aortoiliac, 8 isolated common iliac arteries (CIA), and 2 isolated hypogastric arteries. Preoperative AAA size was a mean 57 mm (range 46-73), and mean CIA aneurysm diameter was 36 mm (range 17-50). All covered hypogastric arteries were patent prior to the procedure. The stent-grafts implanted were 10 Excluder, 10 AneuRx, and 1 Zenith. Clinical outcome focused on mortality and morbidity, including the occurrence and duration of new-onset buttock claudication, which was further correlated with superior gluteal and profunda femoris artery patency.Immediate seal was achieved in all patients. Mean follow-up was 16 months (range 1-54). No type I endoleaks developed from the aortic or external iliac artery, and no type II endoleaks were found from the origin of the hypogastric artery. New-onset buttock claudication occurred in 2 (9.5%) patients, but resolved in both within 4 months. No additional secondary procedures, aneurysm rupture, or aneurysm-related death occurred.Stent-graft coverage of the orifice of the hypogastric artery without coil embolization is a safe and effective adjunct during the treatment of aortoiliac or iliac aneurysm, with a low incidence of buttock claudication.

    View details for Web of Science ID 000238334300019

    View details for PubMedID 16784331

  • Desmoid tumor of the sternum presenting as an anterior mediastinal mass EUROPEAN JOURNAL OF CARDIO-THORACIC SURGERY Saw, E., Yu, G. S., Mell, M. 1997; 11 (2): 384-386


    A 20-year-old man with a large, asymptomatic mediastinal mass was found to have desmoid-type fibromatosis (DF) by needle biopsy. The tumor arose from the internal periosteum of the sternum and mimicked an anterior mediastinal mass. A wide resection of the sternum, including portions of the clavicles and costal cartilages, and reconstruction with a Gore-Tex soft tissue patch were performed. Although extremely rare, desmoid tumor of the sternum should be considered in the differential diagnosis of anterior mediastinal tumors.

    View details for Web of Science ID A1997WM42300039

    View details for PubMedID 9080173

  • THE USE OF SPIRAL COMPUTED-TOMOGRAPHY IN THE EVALUATION OF LIVING DONORS FOR KIDNEY-TRANSPLANTATION 13th Annual Meeting of the American-Society-of-Transplant-Physicians Alfrey, E. J., Rubin, G. D., Kuo, P. C., WASKERWITZ, J. A., Scandling, J. D., MELL, M. W., Jeffrey, R. B., Dafoe, D. C. WILLIAMS & WILKINS. 1995: 643–45

    View details for Web of Science ID A1995QK22500037

    View details for PubMedID 7878773

  • SPIRAL COMPUTED-TOMOGRAPHY IN THE DIAGNOSIS OF TRANSPLANT RENAL-ARTERY STENOSIS TRANSPLANTATION MELL, M. W., Alfrey, E. J., Rubin, G. D., Scandling, J. D., Jeffrey, R. B., Dafoe, D. C. 1994; 57 (5): 746-748

    View details for Web of Science ID A1994NC19000019

    View details for PubMedID 8140637

  • The effect of antibiotics on the destruction of cartilage in experimental infectious arthritis. journal of bone and joint surgery. American volume Smith, R. L., Schurman, D. J., KAJIYAMA, G., Mell, M., Gilkerson, E. 1987; 69 (7): 1063-1068


    In joints with bacterial arthritis, continuing prolonged destruction of cartilage may occur in spite of prompt, effective antibiotic therapy. We measured the extent to which early antibiotic therapy with ceforanide altered the degradation of the cartilage after arthritis due to Staphylococcus aureus had been produced in the knee joint in rabbits. Degradation of the cartilage was quantified by analyses for glycosaminoglycan and collagen. Three weeks after the infection was produced, the cartilage had lost more than half of its glycosaminoglycan whether the antibiotic therapy had been started at one, two, or seven days after infection. Beginning the antibiotic treatment one day after infection reduced over-all loss of collagen by 37 per cent and decreased the area of erosion of the infected articular surfaces. When antibiotic treatment was begun at four, eight, or twelve hours after infection, the loss of glycosaminoglycan averaged 18 per cent. Prophylaxis with antibiotics completely prevented any degradation of the cartilage. Clinical relevance: The findings reported here show how rapidly cartilage loses glycosaminoglycan when it is involved by arthritis caused by staphylococci and how early treatment of the infection reduces the loss of collagen. There is less protection against loss of glycosaminoglycan. The results emphasize the need for early diagnosis and treatment of infectious synovitis and support the rationale for early administration of antibiotics without waiting for identification of the responsible bacteria.

    View details for PubMedID 3654698